View Full Version : Mayday, Mayday

02-21-2014, 01:52 AM
Names Chris. I own a 94 Toyota Celica. I'm having serious electrical issues. I don't have the money to put in a shop for a mechanic to spend days looking for a bare wire or a bad harness, or even a ground problem.

Basically what it is doing is the car is running fine. But I do not have brake lights, radio, clock, heat or a/c, or activity in my dash. Lights come on in the dash but I don't know how fast I'm going, don't have turn signals. Don't know what to do. I've checked my grounds from the battery, I've disconnected my switch at the brake pedal thinking it had something to do with it, I've checked every fuse on the car. I guess I will start replacing my relays. But it seems as though the motor is grounded and the battery is getting a good connection.

Please help me people, I am just a broke furnace man trying to keep this old girl on the road. It was given to me by my grandfather and I have fond childhood memories in this car. It will surely break my heart to take it to the scrap yard.

02-21-2014, 02:53 AM
So, you checked every fuse under the hood and in the cabin? Also, dont these celica's use a cable driven speedo? Never owned a 6th gen, but pretty sure the 5th gen is cable driven.

Did they all quit working at the same time? Anything happen before hand?

Also, maybe crawl under the dash and chase the bundle of wires to where they start, I would think something is unplugged/severed.

02-21-2014, 06:03 AM
Mario had an issue like this. It was a fusable link I believe.

02-21-2014, 06:13 AM
Mario had an issue like this. It was a fusable link I believe.

Marios words:


I went back through again and tested every single fuse in the car again.

Turns out that it was the 100A main alternator fusible link itself. It had blown, but in such a way that it kind of made contact still.
Even putting the thing under a large magnifying glass, it was hard to make out that it was blown. Called Toyota, got a new one and installed it.
Now, Battery is at 13.3V(car running) and the alternator is outputting 14.3V at idle with no accessories and also fully loaded down. So, the Voltage regulator is working as it should.
Tilt Steering = works
Door Locks = works
Key Illumination = works
Everything works as it is supposed to again. I also replaced ALL of the fuses in the car with new ones.

Anyhow, thank you for the help and I am really glad I got it sorted.

- Mario

02-21-2014, 03:59 PM
Also 94+ is electronic speedometer, not cable driven.

02-21-2014, 04:50 PM
Everything happened at once. I was in a drive thru before work, slight incline, holding the brake. Then all of a sudden, the motor started to rev up down. Then the dash, radio, and light flickered. I managed to get it to work, but on the way it continued to do so. When I applied the brake it would shut everything down, then when I let off it would slowly come back. I've disconnected the switch at the brake pedal and nothing happened so its plugged back in. I had a test done on the alternator, which it failed. So I changed it and had a bench test done on the old one. So the old alternator is back in. At this point, it seems that the flickering has stopped, just don't have all of my electrically components working. No radio, no tachometer, no speedo, no clock, no turn signals, no brake lights. I've got tail lights, head light, high beams, and dash lights. Also no wipers. And yes, I have checked ever fuse under the hood and under the dash. I also checked the fusible link on my alternator. Knew exactly where is was because I've been all through that fuse box. Its fine, no melting at all. Thanks for the tip, Mario. But I'm pretty sure that it fine. Thanks a lot to all of you, please keep the feedback coming.

02-21-2014, 05:01 PM
Mario's wasn't melted, and the way it went out was in such a way that it looked like everything was still good. It might need more than just a visual check to make sure everything is good on that fuse-able link.

02-21-2014, 06:27 PM
Mario's wasn't melted, and the way it went out was in such a way that it looked like everything was still good. It might need more than just a visual check to make sure everything is good on that fuse-able link.

Judging by what Mario went through and how it looked fine, I would consider replacing the fusible link. Hell, maybe all of them and the fuses if the it can be done cheaply.

This also may be the best route cause if it's not a fuse/link then it could be major wiring issue and that wont be as easy to look for.

02-21-2014, 06:39 PM
Hey, another WV member!!

I had my alternator fail one time and experianced very similar symptoms. After I had fixed the issue, I was puzzled because several of my lights didn't work. It turned out to be that the surge of power had actually just burnt the bulbs, so thats an idea.

02-21-2014, 08:23 PM
Well boys, I just changed my fusible link. Serious pain in the butt if you don't know what your doing, which I don't. I put it back together, put the battery back in, cleaned the ground that looked to be the one that was for the fuse box, then had everything back in it place and looking as well as possible. Started it up... and I'm right where I started. No change but the fusible link is off of the list. I'm beginning to think that it may be driver's side kick panel fuse box. I'm leaning that way because that is where the fuses for my radio, gauge, turn signals, and brake lights. But it does have IGN fuse, I assume that's my ignition with is working fine. Also, realized that I don't have power windows at the moment, this is also the location for that fuse. Like I said though, it has a few fuses in it that are for things that do work. And I have checked every fuse on the car, they are all good. I wonder if that is an indication that it could be a main power line. Something that has no fuse, or the problem is before it gets to the fuse. I have no clue, just a few things I check out everyday. I guess I'll be doing it until I fix it or give up. Also, I got under the dash and looked at the many clusters of wire and found no tears in the sheaths or any faulty connections.

And to Lonestang, Mountaineers for life brother.

02-22-2014, 02:51 AM
If your power windows aren't working your main power fuse (the funny shaped pink one) could have gone bad, remove it and test it for continuity. You can order it from Toyota, but some auto parts stores carry it, but they don't show it on their websites, so it's best to walk in and check.

02-23-2014, 04:10 PM
Ruled out the main, made sure my brake pedal switch is good, cleaned my fuse box with electrical cleaner, tested every fuse and relay for continuity, replaced the battery(it was down to 7.7v, had a leak), and I don't know what to do from here. Suggestions?

02-23-2014, 11:01 PM
I hate electrical problems. I suck at reading wiring diagrams, but the way to figure this out is to use a voltmeter and simply work backward through the circuits. Check for voltage at the bulb sockets, then work backward from there through any connectors, fuses and back to the supply source. Start with one of the more cimple circuits, like the brake lights.

To me it sounds like either a ground point or a main power source (fuse box supply, fuseable link box, etc.)

02-24-2014, 12:23 AM
Do you have a wiring diagram for the car? I've got the one for the 5 gen but I don't know how common they are between the two. Check the BGB section here and see if it's got the diagrams. I went through something similar with my car several years ago and the schematics help as there are quite a few junction points between the main and the fusebox.

02-24-2014, 03:07 AM
I looked already and the wiring diagram section for the 6GC is missing. I looked at the 5Gen info looking for a common link with all those circuits and didnt find one. They use divverent grounds and I didnt see common connectors. The only thing I saw for sure was that the power source for the engine managment system is outside the rest of the fusable link box, making me think thats why it still runs right but has so many other issues. (all of that is based on the probably flawed assumption that the two gens share some wiring in common).

Without a 6G diagram I cant really offer any other advice beyond just starting at the bulbs and working backwards.

02-25-2014, 02:42 AM
Check for voltage at the bulb sockets, then work backward from there through any connectors, fuses and back to the supply source. Start with one of the more cimple circuits, like the brake lights.

The lazy mans version of this is to start at the end, then pick a point near the middle. If you have power halfway, the problem lies in the second half of the circuit. If you don't have any power halfway, the problem lies in the first half of the circuit. Repeat as needed to find the problem (just keep splitting the problem area in half).

02-28-2014, 07:54 PM
I am now looking into replacing the ecu. Thinking maybe it's just powering half of the car. It didn't give anything on a diagnostic test. Though it didn't give any codes when I tried a diagnostic check a few years ago, before I had all these problems. Thoughts???

02-28-2014, 08:30 PM
I think its grasping at straws. You need to trace the electrical circuits with a voltmeter.

02-28-2014, 08:51 PM
I am now looking into replacing the ecu. Thinking maybe it's just powering half of the car. It didn't give anything on a diagnostic test. Though it didn't give any codes when I tried a diagnostic check a few years ago, before I had all these problems. Thoughts???

I don't think the ECU manages power to everything you lack power to.

02-28-2014, 11:14 PM
Your integration relay probably died. It's the white "box" on the junction block under the drivers dash [not the kick panel]. They're expensive new. :(

Check for 12v at each of the fuses that don't work. All you need is a test light; you don't even have to remove the fuses. There's a small access hole at each side of the exposed end. Best way to check for a blown fuse too; you should have voltage at both holes. If you have no power it's most likely that integration relay, though it might be the junction block as well. And it is possible you have a fried wire. But that's a lot harder for me to pinpoint from here. :)

03-01-2014, 04:47 PM
I looked at the integration relay, had it opened up and everything looked good on it. Doesn't mean it is still good, but to the naked eye it's perfect. I'm going to check all of my power lines to the PCM before I buy a new one. You guys really have helped me a lot, even though it isn't fixed, I've managed to rule a lot of things out. Thanks. Please, more suggestions?

03-01-2014, 05:19 PM
If you're not going to check for voltages we really can't help you, that's the only way to fix an electrical system.

03-01-2014, 11:09 PM
yep. Its why Its my weakness in automotive repair. You (generally)) cant just LOOK at something and see an electrical fault. Simple circuits Im ok with, but throw in resistors and electronics and relays and I get lost real fast. You have to understand the circuit (be able to read a diagram) and then use a meter to find faults. The meter becomes your eyes and your diagram is your fault flowchart.

03-01-2014, 11:37 PM
Like AllTracman78 said, the most likely culprit here would be the integration relay since you already ruled out the ALT MAIN fusible link.
The likelihood of it being your ECU is really low. I mean REALLY low. The ECU only runs the engine. (in an overly simplified explanation)
The circuits you are describing are mostly accessory and subsystem related (Brakes, lights, windows etc.)
The likelihood of all of those systems simultaneously failing individually is again, really low.
That leads to a main point that would control a majority of those systems, for example, the integration relay as being a really decent guess.
(And lets be honest, this is all guessing without any more substantial info ;) But it is a good solid guess)
If you look online at an autowrecker that deals on the internet like car-part.com or somesuch, you could very well find the part you need fora fraction of the cost new.
This would allow you to rule out another major point and not be too far out of pocket.

Please do keep testing out various systems as you are able and post back to keep narrowing it down. If possible try to give everyone here as much information as you are able, like what the readings are and what they should be and which systems are being tested. You know, help us help you kind of thing. :)
If the EWD (Electrical Wiring Diagrams) aren't available here as was said, try picking up a hanes manual from a local autoparts store or online and just take one step at a time. We are here to lend a hand if you get stuck.

All the best,
- Mario

03-02-2014, 12:52 AM
I've got 3 mechanic buddies. NONE of them can get the wiring diagram. Or I would be on that car with my meter non stop until I found the problem. And I can read a wiring diagram, no problem. Just like a blue print, really. Advance doesn't have one either. So I don't know what else to do. Anyone know how to test that integration relay? By the way, mine is brown. Not white, if that makes a difference.

03-02-2014, 08:31 AM
Well, if you plan to keep the car for a while, I'd suggest buying the pair of Toyota shop manuals (BGBs), eBay is your best bet.

03-07-2014, 07:43 PM
I think ive found the problem. Im not getting 12v all through my interior fuse box. Im getting 12.1 here and 5.0 there. So something is going on there. Only problem is... I cant get the damn fuse box out. I can buy one online for pretty cheap if that the problem but ive gotta get it out to be sure, and replace it if need be.

1994 Toyota Celica ST, 1.8L DOHC

Let me know if you guys find anything, ive tried online and had no luck.

03-07-2014, 08:43 PM
The fuse block is nothing more than a junction box. Replacing it would be pointless unless its physically damaged/cracked. There is no internal circuitry. All the fuses/relays are fed directly from the wires behind it. If you tested the fuse connections and found power inconsistencies you need to trace the circuits back to the next junction point before the fuseblock (main relays, main power block under the hood).

If you have partial voltage you have a short somewhere. Probably a main power wire thats rubbed and partially losts its insulation.

Without a wiring diagram and a voltmeter its going to be VERY hard to locate a short. It might be time to take it to a pro.

03-07-2014, 09:45 PM
Here's a wiring diagram http://www.rperrett.net/system_wiring_diagrams.pdf

03-08-2014, 03:32 AM
Well I got the fuse block out and checked all of the wiring. I found that I'm only getting 5v from what appears to be the rear defogger switch. I haven't found it yet but I'll be back on it tomorrow. I have a volt meter and a wiring diagram. If anyone knows where that rear defogger switch is, that would be a big help.

03-09-2014, 02:33 AM
She's back on the road boys!!! Found the problem, it was a wire that had corroded all the way through. Found it in the harness between fuse boxes, under my drivers side fender. Thanks a lot for all of the help!

03-09-2014, 03:31 AM
awesome. good job. Almost exactly as we all deduced. Finding that kind of thing is a huge pain. Glad you got it sorted out.

03-09-2014, 03:48 AM
Nice work, good to hear you got it sorted.

03-09-2014, 11:18 PM
Glad to hear you're back in business.