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View Full Version : Blower not working after swap... Another kink to work out.



Doowstados
01-05-2013, 06:25 PM
Went to turn on the blower yesterday and got no air. The relay clicks but the fan motor won't kick on. I've checked the fuse, and it looks like everything is plugged in.

It worked right before I parked it for the swap two months ago, so it must be something I did while putting in the new engine.

Any ideas?

Hookecho
01-05-2013, 06:35 PM
See if you plugged in the harness to the a/c controls behind the glove box. It's easy to miss and part of the engine harness.

Doowstados
01-05-2013, 06:48 PM
It's the blue plug right? I plugged it in, that was the first thing I checked yesterday.

I'm hoping I didn't damage any wires while pushing it back through the cowl...

Hookecho
01-05-2013, 08:56 PM
If you have a DMM you can check for voltage at the blower with the ignition switch on and fan switch turned on.

Doowstados
01-05-2013, 09:41 PM
If you have a DMM you can check for voltage at the blower with the ignition switch on and fan switch turned on.

I'm getting no voltage at the blower power plug. At the blue plug I have 12v on the black wire, no current on the others.

rizin
01-06-2013, 06:25 PM
First check your 40a heater fuse. The system works off grounding. So with the switch in any position the heater relay will switch so the fuse is supplying 12v to the blower motor. Then the high setting will bypass the resistor and directly ground the other side of the blower motor. So when you have High selected you should get very little resistance at the blower motor plug B-W and a ground point. Any other setting on the blower speed you should get a higher resistance from B-W to ground.

Doowstados
01-06-2013, 08:28 PM
The 40a fuse is good, I even checked it for continuity.

Even on high the blower plug reads no voltage. Is there a chance that the resistor or the switch is malfunctioning?

Ill check for resistance soon.

93celicaconv
01-07-2013, 03:07 AM
On 5th Gen manual HVAC units, the relay activates only when the fan switch is turned from OFF to a speed setting, or back OFF again. The relay doesn't activate between different fan speeds. The resistor only comes into play on the two middle speed settings, not on low or high speeds. So if you don't have a running fan motor at any speeds, it is not the resistor.

It could be the 40A fuse (should check with an ohm or continuity meter to make sure it is good), Junction J5 connector (for blower motor could be disconnected or damaged).

If you turn your fan speed to any position other than OFF, when you depress your A/C switch with the engine running, does the A/C light illuminate to indicate it is functional? If it does, then your relay is good.

Doowstados
01-07-2013, 05:23 PM
The 40A was replaced yesterday and I hooked the fan directly to the battery and the blower works. It just isn't getting any power.

The AC light illuminates when depressed. What is the junction J5 connector?

93celicaconv
01-07-2013, 05:29 PM
The 40A was replaced yesterday and I hooked the fan directly to the battery and the blower works. It just isn't getting any power.

The AC light illuminates when depressed. What is the junction J5 connector?

I'm not at home with my shop manual, but I think the junction J5 connector is the wiring harness connection point coming right off the motor. If you got power for the AC light when the fan speed switch is turned to something other than OFF, your fan relay is working properly, so I believe your fan speed switch has to be working properly as well. We know the resistor doesn't come into play at the lowest or highest fan speed, so that isn't your issue. Almost sounds like there is an open circuit in that wiring harness upstream of the fan motor.

Smaay
01-07-2013, 10:26 PM
it might be the blower motor resistor.

93celicaconv
01-07-2013, 10:40 PM
it might be the blower motor resistor.

Except the resistor isn't involved in the lowest or highest blower motor speeds on this system, and the blower motor doesn't work at any speed (so the resistor can't be at fault if the blower motor does not work at the slowest or highest speed settings).

Doowstados
01-08-2013, 09:05 PM
I spoke incorrectly, my apologies. When I said the light for the AC illuminated I thought I had checked that already, but I did not! It is the heat light that illuminates. The AC does not light up at any position. I also spent the 3.50 and replaced the 40A fuse just in case, no help.

Is this is indicative of a bad AC relay, or bad blower motor relay?

Doowstados
01-08-2013, 09:52 PM
Here's a video of the problem, hopefully it helps.


http://www.youtube.com/watch?v=6h7oZzAXYKU

93celicaconv
01-09-2013, 03:14 AM
OK, that is an excellent video. It helps explain a lot of what you are seeing. It helped me understand where to look for your problem area.

My 93 Celica convertible is in storage for the winter, but I went out and tried to do exactly what you did (turn ignition key to ON position (engine not running), turn blower speed switch on, press A/C button (light comes on), turn blower speed switch off (A/C light goes off, as it should). I can only hear the relay click in the same area as yours when the blower speed switch is turned from OFF to a speed, and then it clicks again when the blower speed switch is turned OFF. It does not click when changing speeds. The relay you are hearing is not the blower motor relay, but rather the heater relay.

First, please access the 5th Gen BGB in this forum. Go to Volume 2 / Air Conditioning System / General Description / Page AC-12. There you will see a simplified wiring diagram that should explain what is going on. Start from the battery. Note the ignition switch (which we'll assume works for now). See the heater & gauge fuses. You said you checked the 40A heater fuse and it was good. The gauge fuse likely is working also (but you will want to verify) because you can hear the Heater Relay click when you turn on the blower switch. Note that after the Heater Relay, power goes to the blower motor (it doesn't work) and the A/C amplifier (through the A/C fuse and the A/C switch) (and if the A/C amplifier is turned on, your green light on your A/C switch button would illuminate, so that doesn't come on either). What does that tell you? Either you aren't getting power through the heater relay when it closes, or you aren't getting battery power through the wiring harness through the heater fuse and through the relay. The relay may click, indicating the coil part of the relay is working, but the power points side of the relay may not be working due to a failure there.

If you got to page AC-39, it will show you how to check the condition of the heater relay. If you apply battery voltage to terminals 1 & 3, you should get continuity on terminals 4 & 5. If you don't get continuity on terminals 4 & 5, your heater relay has failed. In addition, on the socket of the relay (not the relay, but the socket the relay sits in), you should check that you have battery power on terminal 4 (which is on the heater 40A fuse/battery side) - you should always get battery voltage on that terminal. If you do not, you have a fuse/wiring open circuit somewhere between the battery and the heater relay.

Now, where is the heater relay located, you might ask? In the video, when you opened up the passenger side lower kick panel, we could see relay block No. 3 (which is where your fog light fuse, power & control relay is located). The heater relay is in relay block No. 4, which is just above and forward (towards the front of the car) from where your fog relay block no. 3 is located (probably a huge pain to get to). If you go back to the 5th Gen BGB, Volume 2 / Body Electrical System / Power Source / Page BE-8 will show you where relay blocks 3 & 4 are located, and page BE-9 will show you that relay B is your heater main relay (which you must have had access to, as you said your 40A heater fuse was good, and that is right next to the heater relay).

Good luck with this. Let us know what you find out.

Doowstados
01-09-2013, 09:54 PM
OK, that is an excellent video. It helps explain a lot of what you are seeing. It helped me understand where to look for your problem area.

My 93 Celica convertible is in storage for the winter, but I went out and tried to do exactly what you did (turn ignition key to ON position (engine not running), turn blower speed switch on, press A/C button (light comes on), turn blower speed switch off (A/C light goes off, as it should). I can only hear the relay click in the same area as yours when the blower speed switch is turned from OFF to a speed, and then it clicks again when the blower speed switch is turned OFF. It does not click when changing speeds. The relay you are hearing is not the blower motor relay, but rather the heater relay.

First, please access the 5th Gen BGB in this forum. Go to Volume 2 / Air Conditioning System / General Description / Page AC-12. There you will see a simplified wiring diagram that should explain what is going on. Start from the battery. Note the ignition switch (which we'll assume works for now). See the heater & gauge fuses. You said you checked the 40A heater fuse and it was good. The gauge fuse likely is working also (but you will want to verify) because you can hear the Heater Relay click when you turn on the blower switch. Note that after the Heater Relay, power goes to the blower motor (it doesn't work) and the A/C amplifier (through the A/C fuse and the A/C switch) (and if the A/C amplifier is turned on, your green light on your A/C switch button would illuminate, so that doesn't come on either). What does that tell you? Either you aren't getting power through the heater relay when it closes, or you aren't getting battery power through the wiring harness through the heater fuse and through the relay. The relay may click, indicating the coil part of the relay is working, but the power points side of the relay may not be working due to a failure there.

If you got to page AC-39, it will show you how to check the condition of the heater relay. If you apply battery voltage to terminals 1 & 3, you should get continuity on terminals 4 & 5. If you don't get continuity on terminals 4 & 5, your heater relay has failed. In addition, on the socket of the relay (not the relay, but the socket the relay sits in), you should check that you have battery power on terminal 4 (which is on the heater 40A fuse/battery side) - you should always get battery voltage on that terminal. If you do not, you have a fuse/wiring open circuit somewhere between the battery and the heater relay.

Now, where is the heater relay located, you might ask? In the video, when you opened up the passenger side lower kick panel, we could see relay block No. 3 (which is where your fog light fuse, power & control relay is located). The heater relay is in relay block No. 4, which is just above and forward (towards the front of the car) from where your fog relay block no. 3 is located (probably a huge pain to get to). If you go back to the 5th Gen BGB, Volume 2 / Body Electrical System / Power Source / Page BE-8 will show you where relay blocks 3 & 4 are located, and page BE-9 will show you that relay B is your heater main relay (which you must have had access to, as you said your 40A heater fuse was good, and that is right next to the heater relay).

Good luck with this. Let us know what you find out.

The relay checks out okay. I don't think I am getting constant voltage on terminal 4's port though. I put my positive contact for the multimeter in the port and grounded it with the key in the "on" position, no voltage.

Not sure where to go from here as every thing is plugged in...

93celicaconv
01-09-2013, 10:45 PM
The relay checks out okay. I don't think I am getting constant voltage on terminal 4's port though. I put my positive contact for the multimeter in the port and grounded it with the key in the "on" position, no voltage.

Not sure where to go from here as every thing is plugged in...

OK, good relay w/o current flow. Probably OK w/current flow, but one never really knows. Let's assume good relay.

On the relay socket, I would put a 12VDC test lamp or a multi-meter set to VDC, ground the red (positive) lead to the chassis, and then use the negative (black) probe on terminal #4. Does the test lamp light up or do you read battery voltage?

If not, test terminal #5 instead. Does the test lamp light up or do you read battery voltage?

Not absolutely sure which terminal is battery side, but I think it is terminal #4, but test terminal #5 if terminal #4 doesn't do anything.

Also, if you do get the test light to light up or do get battery voltage from teminal #4 (or #5) above, then try this next. With a jumper wire, connect terminals 4 & 5 together on the relay socket. Not sure if you need the ignition key turned to ON or not, might want to try it w/o ignition turned ON, then with. With terminals #4 & #5 jumpered, turn the fan speed switch away from the OFF position. Does the fan motor run now? Does the A/C button light illuminate when turned on?

WIth the above 2 steps, you will at least find out which side of the heater relay has an open circuit. If the last step turns out that the fan runs and the A/C button light illuminates, then do this last step. On the relay socket, with the ignition key ON, put your test lamp or multi-meter set to VDC across teminals #1 & #3. If your test lamp lights up or you read battery voltage, replace your heater relay (it can't carry current through the points). If your test lamp does not light up, there is a problem in the wiring harness on the ignition side of the relay, or your GAUGE fuse is blown.

Doowstados
01-09-2013, 11:24 PM
OK, good relay w/o current flow. Probably OK w/current flow, but one never really knows. Let's assume good relay.

On the relay socket, I would put a 12VDC test lamp or a multi-meter set to VDC, ground the red (positive) lead to the chassis, and then use the negative (black) probe on terminal #4. Does the test lamp light up or do you read battery voltage?

If not, test terminal #5 instead. Does the test lamp light up or do you read battery voltage?

Not absolutely sure which terminal is battery side, but I think it is terminal #4, but test terminal #5 if terminal #4 doesn't do anything.

Also, if you do get the test light to light up or do get battery voltage from teminal #4 (or #5) above, then try this next. With a jumper wire, connect terminals 4 & 5 together on the relay socket. Not sure if you need the ignition key turned to ON or not, might want to try it w/o ignition turned ON, then with. With terminals #4 & #5 jumpered, turn the fan speed switch away from the OFF position. Does the fan motor run now? Does the A/C button light illuminate when turned on?

WIth the above 2 steps, you will at least find out which side of the heater relay has an open circuit. If the last step turns out that the fan runs and the A/C button light illuminates, then do this last step. On the relay socket, with the ignition key ON, put your test lamp or multi-meter set to VDC across teminals #1 & #3. If your test lamp lights up or you read battery voltage, replace your heater relay (it can't carry current through the points). If your test lamp does not light up, there is a problem in the wiring harness on the ignition side of the relay, or your GAUGE fuse is blown.

There is definitely no voltage from either terminal 4 or 5. Also, when I jump the two the blower does not turn on. The gauge fuse is definitely good, and I get 12V from terminals 1 and 3.

Seems like I have a wiring problem somewhere, where should I start looking? I am new to wiring and don't know anything about it but how to use a multimeter, so your expertise is very much appreciated!

93celicaconv
01-10-2013, 03:11 AM
I just check the detail wiring diagram for your vehicle (pages AC-6 & AC-7 in the 5th Gen BGB), and terminal #5 should be hot (battery voltage) all the time (not terminal #4). But you checked terminal #5, and no battery voltage.

I would pull the 40A heater fuse and check if you have battery voltage on either side of the socket that this fuse fits into. If you get battery voltage on one side, then either your fuse is bad, or you have a wiring open circuit between the fuse and the relay (which is a very short distance to evaluate).

If you don't get battery voltage on one side of the 40A fuse socket, it gets real complicated. In this case, my next question is do your tail lights, rear side marker lights, and license plate lights all work? If they do, then you have an open circuit somewhere between the 100A Alternator Fuse (located in the junction block that is up against your battery) and your 40A heater fuse. If you don't have any tail lights working, most definitely check your 100A alternator fuse.

Doowstados
01-11-2013, 01:13 AM
Haven't had the opportunity to check your last couple of suggestions yet, but I have a feeling this wire is somehow involved in this mess:

http://i13.photobucket.com/albums/a265/doowstados/2A60A7ED-D3A9-4E84-AD2A-7E849EFDD670-17267-0000078524A85FE4.jpg

I asked in another thread if someone could I.D. it, but haven't had any suggestions yet. Do you know what it is? It is L(Blue)-Y coming from the same part of the harness that everything on the water neck comes out of. The reason I ask is because on the wiring diagram I see a L wire involved in the power circuit (not L-Y) but these types of things do change over production dates.

Can you verify what it connects to?

93celicaconv
01-11-2013, 04:04 AM
No, that wiring connector has no bearing on your HVAC blower motor issue. It is the factory harness connector to your oil pressure switch, which was original in the front facing - upper driver side of the cylinder head. From your picture, you have something non-factory installed in their now, so your low oil pressure warning light in your instrument cluster is no longer functional.

Doowstados
01-11-2013, 04:49 AM
No, that wiring connector has no bearing on your HVAC blower motor issue. It is the factory harness connector to your oil pressure switch, which was original in the front facing - upper driver side of the cylinder head. From your picture, you have something non-factory installed in their now, so your low oil pressure warning light in your instrument cluster is no longer functional.

See, the thing is my oil pressure switch wire was the yellow one that is tucked back into the harness. That's what is so puzzling about that wire. It's been driving me crazy :laugh: I tucked it in like that when I removed it for my gauge.

93celicaconv
01-11-2013, 01:38 PM
See, the thing is my oil pressure switch wire was the yellow one that is tucked back into the harness. That's what is so puzzling about that wire. It's been driving me crazy :laugh: I tucked it in like that when I removed it for my gauge.

OK. That connector, except for color (my connector is black, but I also have a Rev 2 5S-FE and it looks like yours is a Rev 1, which are different in this area), the physical shape of it is identical to the one I have on my low oil pressure switch. When I get home, I'll look up the proper wire color for this switch. If you are not the original owner of this vehicle, it may be possible a previous owner put in a generic low oil pressure switch that had a different connection, and that owner spliced in another wire in the harness and taped it up a bit to not show the splice.

Doowstados
01-11-2013, 09:39 PM
I have no voltage at the 40A heater fuse. Ill start checking with the 18" or so of wiring coming off the plug behind the dash, because I feel like that is where an open circuit would be most likely to occur.

It could have snagged on something when I put the wiring harness back through the firewall (because it sticks out from the rest of the harness).

I'm not the best at reading wiring diagrams, can you explain to me how to figure out which wires on that plug should carry current and which shouldn't? The only one I am getting voltage on is the black one.

93celicaconv
01-12-2013, 03:45 AM
I asked in another thread if someone could I.D. it, but haven't had any suggestions yet. Do you know what it is? It is L(Blue)-Y coming from the same part of the harness that everything on the water neck comes out of. The reason I ask is because on the wiring diagram I see a L wire involved in the power circuit (not L-Y) but these types of things do change over production dates.

Can you verify what it connects to?


I asked in another thread if someone could I.D. it, but haven't had any suggestions yet. Do you know what it is? It is L(Blue)-Y coming from the same part of the harness that everything on the water neck comes out of. The reason I ask is because on the wiring diagram I see a L wire involved in the power circuit (not L-Y) but these types of things do change over production dates.

Can you verify what it connects to?

An L-Y (blue wire w/yellow stripe) is used in the to feed power to a lot of various items, including: clock, ignition cylinder light, door courtesy lights, door warning light (instrument cluster), luggage compartment light, auto antenna relay, radio (or radio amp), door locks, rear right speed sensor (if ABS equipped), electronic controlled transmission solenoid, air conditioning magnetic clutch relay, just to name a few. There are likely additional items. But I don't see where a L-Y wire should be in the location you have yours in. This is a significant mystery.

I would still think that the L-Y wire is a 2nd wire spliced in to the orignal low oil pressure switch by the original owner because of a potential problem with the original wire connector, and you just happen to now have 2 (the original owner happened to use a different wire color source but it had the same connector on it). I think if you opened up the wiring harness a bit farther where it is taped up, you will see those 2 wires taped together.

93celicaconv
01-12-2013, 03:57 AM
I have no voltage at the 40A heater fuse. Ill start checking with the 18" or so of wiring coming off the plug behind the dash, because I feel like that is where an open circuit would be most likely to occur.

It could have snagged on something when I put the wiring harness back through the firewall (because it sticks out from the rest of the harness).

I'm not the best at reading wiring diagrams, can you explain to me how to figure out which wires on that plug should carry current and which shouldn't? The only one I am getting voltage on is the black one.

No voltage at the 40A Heater fuse connectors indicates an open in the W (white) wire feeding that fuse connector. There is a 4 wire harness connector at the plug behind the dash. If you look for the white wire attached to pin terminal #3 of the female side of that connector, you can check if you have battery voltage at that terminal. If you do, then you have an open between that connection point and the fuse - which I think you said was 18" long. If you don't have battery voltage at that terminal, then you have an open on the female side of that connector, between it and the 100A Alternator fuse.

If the latter, that will be extremely diffiult to find. You might want to consider putting a new, seperate wire from the positive terminal of the battery to pin #3 on the female side of this 4-wire harness connector (splice it in just before the female connector) - and that should restore your power.

Doowstados
02-05-2013, 06:25 AM
An L-Y (blue wire w/yellow stripe) is used in the to feed power to a lot of various items, including: clock, ignition cylinder light, door courtesy lights, door warning light (instrument cluster), luggage compartment light, auto antenna relay, radio (or radio amp), door locks, rear right speed sensor (if ABS equipped), electronic controlled transmission solenoid, air conditioning magnetic clutch relay, just to name a few. There are likely additional items. But I don't see where a L-Y wire should be in the location you have yours in. This is a significant mystery.

I would still think that the L-Y wire is a 2nd wire spliced in to the orignal low oil pressure switch by the original owner because of a potential problem with the original wire connector, and you just happen to now have 2 (the original owner happened to use a different wire color source but it had the same connector on it). I think if you opened up the wiring harness a bit farther where it is taped up, you will see those 2 wires taped together.

I figured it out yesterday, with your help!

Just before I ran the wire from the battery to the fuse I noticed a small, black, non OEM plug that was attached to the harness and hidden by the loom. Turns out it had continuity between the fuse terminal and the plug, so I put a new ring connector on the battery terminal and the heater is now working. It seems that the PO added this wire at some point.

Thanks!

93celicaconv
02-05-2013, 03:33 PM
I figured it out yesterday, with your help!

Just before I ran the wire from the battery to the fuse I noticed a small, black, non OEM plug that was attached to the harness and hidden by the loom. Turns out it had continuity between the fuse terminal and the plug, so I put a new ring connector on the battery terminal and the heater is now working. It seems that the PO added this wire at some point.

Thanks!

Sounds like the PO had the same problem you were trying to work through, except he had it in the original wiring harness, and you had to find it relative to what was wrong with what the PO had previously done. Great job diagnosing and fixing the issue, Doowstados.