Headlight circuit not working (bad relay?)

[Dan]

Hi,

I have a 1987 DL Wagon, and the left low-beam circuit isn't working. When I
turn the headlights on (low-beams), the left side low-beam unit, the white
running light and the amber side light all don't work. However, the left
turn signal works fine, and when I turn on the high-beams, both headlight
units on the left side come on (the car has a total of 4 sealed bulb units).
This would appear to indicate that all bulbs are working OK. I've also
checked all of the fuses.

I'm guessing there's a bad relay. I don't know where the headlight relays
are, so any help would be much appreciated. I have the Haynes Repair Manual,
and it shows the relays on the wiring diagram, but I couldn't find 'em while
I was poking around under the hood or under the dash.

Thanks!!
-dan

 

[johninKY]

There are 4, maybe 5, relays in a row directly behind the instrument
cluster. I noticed them when I once swapped out the dash. Never had a
relay problem si never identided these relays but I suspect here is where
you'll find the headlight relays.

 

[Dan]

Turns out it wasn't the relay; well at least, it seems not to be.

The low-beam light was out, as well as the 2 side marker light bulbs. I'm
not sure that they all went out together, but it seems kinda suspicious.

Any thoughts?

 

[mulder]

Turns out it wasn't the relay; well at least, it seems not to be.

The low-beam light was out, as well as the 2 side marker light bulbs. I'm
not sure that they all went out together, but it seems kinda suspicious.

Any thoughts?

Check the system voltage. It is possible the regulator is bad and the
voltage is too high, this will cause bulbs to blow prematurely. With a
voltmeter on the battery terminals with the engine running you
shouldn't see more than 14.5 volts or so. If it's a lot higher, like
15-16, that could be your problem. I don't know if your car has an
internal (in the alternator) or external regulator, if it's internal
and NG the alternator would have to be replaced.