lighting issues
 

ok my name is travis and i just started the forum. i have recently replaced my engine and transmission. in my 89 toyota supra T and my lights are wanting to do something strange that i have never seen before ok.


here is how i slove the problem, when i take the dome fuse out of the engine panel the lights work perfect and the headlight motors and all that and the horn, well when i put the dome fuse back into the panel the lights go haywire. if i turn them to the off position on the multifunction switch the lights turn on and vise versa. and the motors wont work and my horn wants to stay on all the time. well i was wondering if anyone has run into this problem and if so hit me up with some info please.

I think it has to be a wire that is grounding out. Just check the wires and see what you find. Thats about all you can do. Or just leave the fuse out. lol

Check along the circuit that the dome fuse is part of and like he said, check to see if there is anything shorting out. Shouldn't be that hard. I would first look in the engine bay where all the recent work was done. Get a manual for the car. This car has alot of circuits that are intermingled. All because of the damn integration relays it has.

i had a similar problem... kinda.. i used to push my horn and it would activate my lights ?!!?!! didnt know for the life of me what was causing it but didnt mind it cause dont use my horn anyways, anyways it ended up just being wrong fuse in wrong place in in the under hood fuse box.. so maybe even making sure all fuse slots are filled with right fuses i guess, good luck.

Go ahead and test the line for a short to ground. The difficult part of troubleshooting that particular circuit is the number of devices which receive power from it (clock, radio, security system...).

The first thing I think of after reading your post is the security system.

the car doesnt have a security system. but i think that the dome circuit is getting a feed. a positive so when i make a connection by putting a fuse in the slot, well it completes that feed and makes everything go haywire. thanx for the responds guys i appreciate it and i hope to talk and help yall to alright thanx agian

All USDM MKIIIs came from the factory with a security system installed. I've seen it diagnosed as the reason for lighting issues as well (either due to a poor removal job or a fault in the unit). The main reason I'd check the security system is because it integrates with the retractor control/integration relay #2. If the security system was removed I'd go through and verify all the wiring modifications.

cre when i got the car there wasnt a security system in it and all the wiring was working properly. this happened after i replaced the engine the integration of the wiring is fine i think i just cross refrenced some wries and its making it feed into the dome fuse. its not blowing my fuse so its not making things go crazy so i think its something like my head light (rh) & (Lh) is intwined with the dome fuse so im gonna check that next time im at my shop. but i do thank you for your smarts and knowledge on helping try and figure it out. i know all us supras came with a security but from factory you can get the security feature tooken out its a added feature that if you didnt want to pay for you didnt have to. just like the targa top. but i thank you agian for your response and i will def keep your knowlegde in mind

Ok, sorry, you'd just be surprised how many people think they didn't come with one simply because they just never payed attention. ;) I've never heard that you could special order a MKIII without a security system. I'm going to have to look into that further. If anything I suspect that's just something the dealer offered as the is no p/n for a wiring harness without provisions for the various components, nor are any of them flagged as options in the EPC from Toyota.

If the head lights come on but don't rise when you install the dome fuse a short across either the feed for the headlight relay coil or across both HL fuses is a possibility (the relay's more likely).

If they pop up and turn on then it's either a short across the green wire with the red stripe which runs from the switch to pin #3 of the Integration Relay #2 or the line which used to run from the Integration Relay #2 from the former stock security system (yellow with a blue stripe).

Of course there are other possibilities, I'm just trying to point you in the direction of the most likely candidates.

Mine has one but i dont know how to engage it when i bought the car all i got was a key but i know it works b/c one day when i went to unlock the door and it just went off out of nowhere lol. and then the car wouldn't start so i had to disconnect the battery and reconnect it. Does anyone know where to get the stock keyless remote or is it even worth it to pay the money to have it. I dont know how sensitive the alarm is. Or should I buy a whole new alarm setup.

def a poss. but like what i was think while reading what you typed is they still do it when i dont have the headlights on. and what gets me while im trying to tifgure this out i think about the grounds i found a bunch of grounds i didnt know where they went so i put them all together on the car. and i might have gotten a power feed line and that might be causing it so im gonna try taking individual trial and error to fix it and maybe that will fix it but im not shure.

i would honestly recomend a car alarm to anyone who buys a car not just for conveince but for also a self reilief that your car is more protected like if you go a high dollar car alarm then ive touched my car and it went off so i mean i would rcomend a car alarm to anyone

The factory security system is a rather simple device. It's armed and disarmed through a switch attached to the back of the lock cylinders. Not surprising that most don't function properly these days after years of wear and tear. The system has sensors at both doors, hood and hatch and when triggered disables the starter, flashes the headlights and honks an auxiliary horn (it's the one by the brake booster).

In '91 and '92 Toyota offered a supplimental system as an option which added a glass breakage sensor and keyless entry.

With both types to re-enable the starter you must rearm the alarm and then properly disarm it. From what I remember, pulling the battery cable doesn't reset it unless the latching relay inside the security system's control box is no longer latching when thrown... I know it doesn't reset mine, although it's been a while since I've dissected one so I could be remembering things incorrectly.




EDIT: The upgrade kit for the '91 and '92 isn't plug and play for older models, nor has it been available for years.

The stock alarm ONLY uses switches, these monitor locks, doors, hatch and hood. If someone breaks the glass but doesn't unlock the door or open the trunk, it does nothing.

I too highly recommend investing in an aftermarket alarm. Me, I've kept both and they're thoroughly integrated with eachother. I also recommend getting an alarm with paging capabilities.... or one that screams in a female voice when triggered. ;)

That's entirely the reason I mentioned the security system (or if the controller is absent, even the security system's wiring)... The security system bypasses the switch.