Headlight Relay (High Beam)

[tartan18]

A strange thing has cropped up with my car's lighting system (1975). When the headlight switch is in the OFF position the turning indicator blinks as it should but when the engine is running the switch in the middle position turns on the high beams. The side markers and the turning signal lights work as they should -- just no indicator light blinking. In the third position the headlights add the low beam -- the stalk doesn't switch from high to low or low to high. The turn signals work in all three positions but only has the indicator blink when the headlight switch is in the OFF position. And I can't figure out why the high beams come on in the middle switch position. To add to the mystery, when the engine is OFF the headlight switch in the middle position turns on the headlights and the side markers.

Last year I installed the IAP headlight relay kit (up until yesterday it worked perfectly). I also did the brown wire fix last year. I've checked both of the IAP relays and all associated fuses and grounds -- but clearly I am missing something -- where should I start looking? I also wonder where the car's original headlight high beam relay is located -- according to the shop manual this relay is an unprotected circuit and I understand the IAP kit taps into the original relay.

Any ideas would be appreciated.

[vandor]

Originally there is no relay for the high or low beams. I am not sure what the IAP kit does, so can't really say where to look.
Otherwise it sounds like a grounding issue, where once circuit feeds another because of poor ground. I would look at the grounding points of the front turn signals and the headlights.

[aj81spider]

The IAP kit plugs into the existing light sockets, and shouldn't have anything to do with your problem. You can verify that by unplugging the kit and plugging the bulb into the old socket.

[geert]

check the grounds .

-are the turning lights working at normal speed ?
- did you work on or under the dashboard ?

problems with the switch(es) is another possibility

keep us informed,

groeten, Geert.

[bobplyler]

just no indicator light blinking.

My car did that for years. Except the indicators never blinked. But the external lights worked fine. I just put the "brown wire fix" on my car this weekend. Now, the indicator works, the interior lights aren't worthless, and the headlights now put out whiter light (not yellow anymore).

[tartan18]

Thanks for all the suggestions -- keep them coming. Today I began tracing the wiring from the headlights toward the firewall. All grounds up front and in the engine bay are good (used a ohm meter). I did notice that when I move the headlight switch from OFF to the middle position I can hear a relay click from somewhere in the dash so that is my next area to check. I did not do anything with the dash or electrical system before this began happening. The turn signal indicator blinks at the same pulse rate as before (normal) and the turn signals continue to flash even when the indicator doesn't light up -- but the headlight still come on with the light switch in the middle position.

Very aggravating.

[bobplyler]

Perhaps the headlight switch is bad.

[geert]

You're sure your beloved Fiat didn't came near a sick English car ??

- there are ground wires under the dash too ( don't know about a 1975, but normally at the iron rail under the dashboard ).

- If you hear the relais ( under dashboard, central ) , that means highbeams are on, at the moment that it shouldn't considering the position of your lightswitch : and the switch between high/low doesn't work because it's bypassed : faulty switch ? ( position 1 gives contact to position 1 and 2)
disconnect the wires of your lightswitch ( left dashboard) ( notice positions ) and make with those and a little wire a simulation of position 1 & 2 ( or connect another switch)
If that switch is faulty, it's easy and cheap to substitute ( or to repair if you can open it ).

succes, Geert.

[tartan18]

Still trying to find the cause of my headlight/side marker problem. I believe it is the headlight switch itself so I am going to order a new one. I've cleaned all the ground connections in the dash itself. I do have a question -- this relay runs the hazard flashers. I've checked several of the vendors and I can't seem to find it listed. Any ideas where I can get a replacement?

[tartan18]

At long last I found out what was causing my headlight/side marker and turn signal problems. The bulb that lights the fiber optic strands was pulled out of its socket thereby disconnecting a ground that affected all the above. Plugged the socket back in and voila, everything works. Case closed. Much thanks everyone.

[Turbofiat124]

At long last I found out what was causing my headlight/side marker and turn signal problems. The bulb that lights the fiber optic strands was pulled out of its socket thereby disconnecting a ground that affected all the above. Plugged the socket back in and voila, everything works. Case closed. Much thanks everyone.

The headlight switch on my 80 Spider had a delay action. It may take a second or two before the headlights would come on. Sometimes I could turn it on and off several times and get them to come on.

I originally thought it was my headlight relays I wired up. Turns out the headlight switch was bad. I replaced it but there was a note some models it says requires slight modification. My guess is perhaps the wires on earlier models are mixed up? So that would explain why your headlights come on in the middle position.

Normally in the middle position the parking lights will burn with the ignition on or off.