Electic short? Where do I start hunting this one down?

[Grandavi]

2 days ago, my 87 MKIII started doing something odd. I noticed while looking at it from my living room window. The Battery light was on and the door ajar light was on. (and.. so were the door lights that are at the bottom corner)

I dont have an interior in the car from the front seat back, so all that wiring is exposed and I can unplug the door switch if necessary, but wondering why the battery light would be on. Noticed that the top post of the alternator is slightly loose (tight, but not so tight you cant twist the wires on top). I dont know if that would do it or not. Everything works fine, except the damn battery and door ajar light will not go off (I think the battery light may be because my battery is low from the door ajar light and door lights being on.. although.. I didn't think that would pop on while the ignition is off.

Is this an ignition issue? Anyone heard of this happening and have some "time saving" recommendations before I start hunting the wire jungle?

Thanks!

 

[barkz]

battery light will NOT come on unless car is on. but you said theres lots of bare wires, something could be part of ignition wires and is grounding out. have you checked TSRM for wire diagram? sounds like this thing is a project, i would just disconnect battery whenever you dont need juice.

 

[Grandavi]

Yeah, the key is off and out of the ignition barrel.. but the battery light stays on. By bare wires, I mean the interior is out (nothing from the front seat to the rear hatch... )
The TSRM diagram is a bit beyond my tiny brain.. lol. I can follow it and understand most of it, but the application of it from book to car is another story. The front seats and door panels, etc is in the car. Behind that seat, its all been removed (interior).

I was thinking it may be the ignition barrel (where I put the key to start the vehicle) shorting, but I dont see any problem with it. The quick fix is just to hook up a switch between the car and the battery and then just turn it off, but its winter approaching, so after a week or so, the car wont be on the road anyway, so I wanted to see if I can fix the issue. Just hoping someone has seen the problem before and knows the general area I should start. I would like to avoid removing the dash if possible.

 

[barkz]

oh ok so no bare wires then? could be the key cylinder, or ignition switch, somehow sticking on or internal issue. stick the key in and turn it off and on a few times hard/quick. something could be sticking in there?

 

[Grandavi]

Yes, it could be inside the barrel itself. No bare wires that I can see. Going to play with the cylinder and see if the internals are a bit loose after 23 years.. will see if that changes anything (although.. the door lights should not be on regardless what the key cylinder is doing.. as that doesn't control those lights in anyway. Wondering if the dimmer switch could be faulty causing this.. (only say that because I have heard that there are problems with the dimmer.. so naturally my brain jumps there)
(bow to Yoda.. love the car)

 

[barkz]

dimmer would ony do just that...dim. i wired my boost gauge into the dimmer and theres only 3 wires, power in power out, and im not sure of the 3rd one. but that shouldnt effect door/dome lights.

 

[GrimJack]

Try unplugging the door sensors.

 

[barkz]

mine are junk, sometimes the dome light will come on when door is opened, but only drivers side. and ive never noticed if the door panel lights even work

 

[Grandavi]

well.. I can access the wire for the door button easily (as it doesnt have the rear interior in it). Unplugging it will take care of the door lights, but not necessarily the underlying cause.
How do you unplug these (anyone know?) I am looking at where they are joined and it looks like you lift a tab, but it doesnt lift. (maybe brittle due to time?) If anyone has a quick answer to that, I will unplug both and then start testing, just want to avoid breaking them with stupidity.. lol.
The battery light did disappear after jiggling the key in the key cylinder. But it comes on when the engine is running (would an alternator fault cause this? I know it could cause the battery light issue.. but doubt it would the door ajar issue.. ) Could be bad timing for me as it was working fine until 2-3 days ago. Could be 2 issues, one caused by the other.

I hate hunting wiring issues.. hehe. I am just not very adept at electrical circuit testing.

 

[GrimJack]

If unplugging the door sensors takes care of the door lights, then the door sensor(s) are faulty.

 

[thedave925]

Those plugs for the door sensors are a PITA.
Get a jewelers flat head screwdriver and shove it under the hook portion of the connector where the plug tab is hanging up on, in the direction the plug is inserted into the female.
The sun doesn't hit that plug (normally lol) so it should take the stretching

 

[barkz]

yes bad alt wont charge battery, giving you the light....or the battery is really weak now. check your wires at the alt, and might as well throw the battery on a charger overnight too.

 

[Grandavi]

I boosted it, took it out for a run (its an exercise machine driving it... without the PS pump attached... ) Damn this car is fun though.. lol

The battery light is off now, but the door lights are still on. the car charged itself while driving for 1.5 hours so I believe the charging circuit is right, however, previous owner has some weird wiring going on under the dash from stereo installation and turbo timer. I have to trace what was done and figure out what is changed under there. Most seems original so shouldn't be a problem.

Now.. to find the time to really hunt. The driver side door light died too.. lol. I dont know if it was me pulling on the wire or if it was just on too long.. have to fix that as well. Supra heaven.

 

[thedave925]

The door light switches are really ground points that make contact when the door opens.
If they were bad, the courtesy lights, ignition ring, map light wouldn't come on.
The outside door handle switch (when you pull on it the interior lights up, even if locked) will also activate them.

There is a relay box (Integration Relay, found at passenger kick panel) that runs all the interior lighting. It also controls the dimming effect.
I haven't heard about Integration relays going out... but it can happen. Headlight retractor relay has a power lead in the mix too

This calls for some EWD homework to figure out what color wire your looking for and then find/trace it in the car.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=D&P=23

Just some thoughts:
After staring at the runs on there awhile, maybe your hatch is not shut completely/switch is frozen open, keeping some interior lights on which run down the battery.
Or that the ignition barrel is getting dirty contacts and 'off' isn't completely off anymore, also keeping on some lights and running your battery down some.

Still doesn't explain why the battery light is on when the key is out unless the ignition barrel has a frozen AM2 switch in it...
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=D&P=3
B-O wire off AM2 of ignition switch is positive lead 'I', which powers battery warning light found at EWD 1-8. Warning light shares a run with Wire Yellow-Green stripe at the alternator.
It was mentioned that the wires at the alternator were LOOSE? Maybe the Y-G (not in the plug at rear of alt.) is grounding?

Ideas to check without digging to hard into wiring:
-driver outside door handle switch (contact grounds when handle is open), check it isn't frozen. You may have to pull the door panel to get to the lower connector. Pull that plug and see if there is continuity.
-Is your hatch fully shut? there's a switch for when thats open too. Maybe the switch is sticky?
-switches are in all the exterior key cylinders. Work them all make sure the switch isn't grounded, they keep power on to the integration relay.
-alternator Yellow-Green stripe wire mounted at ring terminal, it reads load and shares that battery warning light, check that it isn't grounding. Pull it and check continuity to the nearest ground. If there is continuity, your problem is elsewhere.

Wiring is a lot of studying lol

 

[Grandavi]

The battery light I believe is attributed to a stacked wire connection on the top of the alternator. It cannot be tightened enough without risking ripping off the screw, so I will have to vamp one wire into the other. I took the door switch wires off and the light went off (the driver side door switch is the one that seems to be linked to the problem, it is also the door light that isn't working). I believe I also have a ground fault somewhere as well that isn't affecting anything obvious.. its just one of those things that little issues seem to point at. I also think that the ground issue is linked to the stereo, so I have to pull it to see how it is patched into the dash harness.

The headlight (driverside) will not raise (it works, but it wont go up, you have to manually turn it) and was like that when I bought the car. Not sure if its a wiring fault or the motor. It will go down half way when I turn the lights off, but it cant raise. I may need to replace the motor assembly (doesnt look like it will be a very tough job.

So, where I sit is ... door buttons are disconnected. Car is going to sit for 2 days and I will see if there is still a draw on the battery that will kill it (2 days was the max before and I would have to boost to start). Meanwhile.. I have to look over the wiring. The reverse light wire to the transmission seems like it is busted somewhere (those lights dont go on).

Thanks "theDave" for pointing out which wiring diagrams I need to look at. I have the physical TSRM, so now that I know where to look, I can track it easier.

we will see what happens. For now, the door switches are unplugged (dont really need them, as I find them a "convenience" but in over 25 years of driving I have never had a door ajar while driving.. lol.

 

[thedave925]

The head light motor assembly is time consuming with awkward placement of bolts and wrench space.
Check the motor is getting power/is grounded well before dismantling.
The RTR fuse powers Integration Relay 2 aka Retract relay.
This Relay also shares a wire with Integration Relay 1 (something to do with when you leave the head lights on but turn the car off the lights go off even if the housings don't retract EDIT: or is it when you open the door they go off?) and another item I can't think of atm, tight on time to leave for work lol

The reverse lights get their power from the engine harness which is like a 3' extension to connect directly over the tranny.
Its easy to miss connecting this one when dropping in an engine, like if you don't have the harness on the long block assembly before install.
When I first got my Supra, this was also the case. I protected the brake lines behind the head at the fire wall, completely dismounted the rear engine/transmission mount for space, and with a light and couple extended long needle nose pliers, mated the plugs. 1.5hrs of cursing and road debris in the eyes....

 

[Grandavi]

The headlight motor seems to function, although.. not fully.I havent really looked at the TSRM for setup on it, because it will lower/raise if I turn the screw (adjustment) on the side with no problem, but I am wondering if maybe someone pushed down on it, because if I turn off the headlights, it will retract 1/2 way. So, if I turn the screw so that it aligns correctly to the hood, when I turn it on, it comes up 3/4 way. So, the motor is at least partially functioning. Then if I turn the screw so that the headlight is open fully, and turn off the lights, it only goes between 1/2-3/4. So, it may be a matter of adjusting it, or there may be a broken gear inside the motor... although it makes no noise. I believe it is a worm screw.. again.. I will find that problem when I look at the TSRM.. its probably outlined in there.

I have to put on a Speedo cable so I will work with the reverse lighting at that time (I think this is a W58 tranny, originally I thought it was a R154). Cant do the "under car" work until I get my 88 interior completely put back in or completely removed (stalled while I decide because I have to get the car painted so removing it entirely (except the dash/carpet/console/front seats/door panels) may be the best option so that exterior trim removal is easy.

so much work.. so little time.

Also, I unplugged the door wires and there is no drain. The battery light will come on intermittently and I believe it is the key cylinder (ignition) that is the culprit. It only does it every 3-4 times I turn the car off, but there is no drain coming from the battery (nothing that would kill the battery anyway) so I think the door button circuit is the fault for the door ajar light. Could be inside the driver door as that was the light that wasn't functioning. That will also have to wait until I finish up with the 88.

Now I notice the car leaks gas from the tank, maybe the downspout gasket. Same issue I have with the 88 when its over 1/2 full, but I will have to inspect the entire tank, because the car is very low, the previous owner may have hit something coming out of some area that punctured it (not likely, but I will have to search anyway). Just gives me something more to do with my free time when I find it again.. lol