dukecebrelli

I don't have my chilton handy- the headlights wont turn on- all fuses look good- I think the switch is ok- before this happened they would work for a while- after some time of driving they would flash- someone told me it might be the headlight relay

...anyone know where the headlight relay is located?
(1987 htch bk)
Thanks

65Z01

The FSM for my '88 shows no headlight relay, only a circuit breaker in the light switch.

CFI-EFI

Leave the Chiltons under the tire to keep the car from rolling and get yourself a FSM. The headlight relays, there are three of them, are under the relay cover that covers all three of them on the front of the left front wheel well. "Someone" should tell you that the headlight relays are only to power the headlight actuation motors. The head light bulbs are powered directly by the headlight switch, through the dimmer switch. If the headlights have been flickering, chances are you have a short in a headlight wire and the flickering was the breaker blowing and resetting. I'm guessing it is time to break out the old DVOM and go short hunting. You may have to replace whatever it is you burned up, if anything, by not fixing it sooner.

RACE ON!!!

TPIGUY

Most GM light switches have a thermal circuit breaker built into or mounted on the switch. A high current draw (short) will cause the bi-metalic strip to curve, turning off your lights. Once the strip has cooled, your lights will come back on. This was GM's idea for "limp home head lights" You may have a short it your headlight wiring, indicated by the lights staying on for short periods of time. If they stay on longer, it's probably time to replace the switch. They get old and worn out like the rest of us>

AGENT 86

http://members.shaw.ca/agent86/Headl...0Foglights.pdf
http://members.shaw.ca/dankai/Headlight%20Doors.pdf

SportsCarsUnlimited

Check the headlight grounds, these are for the lights only not the opening or closing of the headlights, there on top of the frame rails between the headlights and the radiator on both sides. There's a 10mm bolt holding them down. If there not opening or closing check the relays, there's a main and a left and right relay. if your having the same problem with both sides check the main relay.
David

SportsCarsUnlimited

Hello CFI-EFI
(Leave the chiltons under the tire to keep the car from rolling)
I could not of said it better, Why do they sell those crappy books. I use the GM service manuals only, They cost a lot more but tell you what you need to know.
David

Harryscarlot

those Chilton books are good for showing you where to locate the battery, or how to change your wiper blades
start a campfire with it

Redeasysport

Your problem is obvious your reading the wrong book

c4cruiser

The Chilton and Haynes books are best used as an emergency backup paper supply for the outhouse.

CFI-EFI is correct. As long as the headlamps are rotating up and down, the relays are fine.

FWIW, the relays are still available as an AC Declo part. There are two different relays used. There is a relay for each of the headlamp motors and the 3rd one is an isolation relay which changes the polarity of the motors so that they run backwards when lowering the buckets.

Headlamp Motor Relay: GM p/n 10031018
AC-Delco p/n: D1784

Isolation Relay: GM p/n 10039962
AC-Delco p/n: 15-2386

dukecebrelli

thanks a lot guys! New switch it is... as for the chilton... I really did use it to sop up some spilled beer last night

CFI-EFI

STOP!!!

Don't just run out and buy a head light switch. It could be just fine. You may have an over load, or a shorted wire blowing the breaker. Now that we've told you how it works (available in the FSM), it is up to you to do the final diagnostics.

RACE ON!!!

dukecebrelli

ok- newbie question here.... what is FSM?
Thank you for the info everyone

65Z01

Field Service Manual is published by HELM and provides mechanical & electrical information on your particular Vette. It is THE service manual to own when doing any work on your Vette.