Headlight problems?

[silvergsx623]

on my 89 supra the head lights stay on all the time, if the battery is hooked up. IF i twist the headlight switch, they will pop up and high beams work. if i twist the switch off, they will go back down , but the lights will stay on...:nono: lol

Any ideas?

where should i start

Thanks

 

[silvergsx623]

Anyone have anyidea why the headlights wont turn off?

 

[AF1JZ]

Only thing that I can say is to check the wiring for shorts maybe or the fuses. Sounds weird though.

 

[JonoTurbo]

Do you have an 87-88 harness in the car? If so, that's the cause. A friend of mine had the exact same problem. I think it has something to do with the connection to the headlight relay from where the wiring harnesses meet near the ECU.

 

[Steve_N]

From the TSRM Elec. Section (TEWD) diag. looks like the problem is with the combanation switch.

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?Section=Main&Page=060

If it was a fuse,short, or relay either the lights, retract motor or both would not work.

HTH

 

[silvergsx623]

i have the 89 wiring except for the engine harness, its out of my 88.

is there a way to test the combo. switch?
where is this switch located?

thanks guys

 

[Nick M]

If you look at the link to the EWD posted, you will see it is nearly impossible for the factory system to do what you are describing. The integration relay powers the headlamp relay, and the motors for retracting.

The ground path is different for high and low, low is through the switch, but power is still from the head lamp relay, which the integration relay controls. If the car is not hardwired wrong by somebody, either the integration relay's transistor control is malfunctioning, or the wrong harness is giving you bad grounds and short to power sources. Bad grounds will wreak havoc on your attempts at dianostic work.

 

[silvergsx623]

ok thanks, that makes sense. I'll start checking the wiring and grounding points.

 

[JonoTurbo]

i have the 89 wiring except for the engine harness, its out of my 88.

is there a way to test the combo. switch?
where is this switch located?

thanks guys

If you have an 88 engine harness and an 89 car that's your problem. A friend of mine had the exact same setup and the exact same problem.

I never was 100% sure of the solution to this problem, but my guess is the culprit is a red wire with a yellow stripe that goes to the headlight relay from the junction area where the ecu is. On the 89+ body side it should be connected to B2 pin 4, and on the '88 engine harness side it originally was B1 pin 22. If this wire is grounded somewhere, by being connected in the wrong spot, it will cause your headlights to be on all the time as you describe.

 

[silvergsx623]

thank you!

I'll check into that sunday


where is the headlight relay?
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?Section=Main&Page=15

i can't locate it

 

[Steve_N]

thank you!
where is the headlight relay?
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?Section=Main&Page=15

i can't locate it

Its the integration relay No. 2 in theat link

Main Headlight Relay is in the engine compartment fuze box.

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?Section=Main&Page=18

HTH

 

[silvergsx623]

Its the integration relay No. 2 in theat link

Main Headlight Relay is in the engine compartment fuze box.

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?Section=Main&Page=18

HTH

Thank you!
exctaly what i needed