93 loyal dim left headlight, no left tail light and no dash lights

[mikaleda]

i had this 93 loyal wagon come in to work the other day and its got me stumped, the left headlight is dim on both high and low, their is no left tail light and the dash lights arn't working.

i checked the head lights fuses and they were both good, so i checked voltage at both head light fuses, left had 2.5 volts both sides of fuse and the right had 12.5 volts. I unpluged the left head light fuse and it doesnt affect the head light, it stays on and stays dim, so i started checking the relays. I found one relay with 12.5 volts on one side and 2.5 volts on the other side and the relay was hot to the touch, so im fairly sure there is a short of some kind going on. what is stumping me is that the left head light stays light (dimly) even when the fuse for that head light is disconnected, and that none of the fuses are being blown. this car came in once before and the problem was there then but it would happen infrequintly, ocassionaly the dash lights would turn off and the left head light would dim, but tapping on the top of the dash would make the lights turn back on and the head light would be bright again.

 

all sighns seem to say something is shorting out, possibly from the right head light to the left as well as a ground to hot. also it sounds as though the problem could be in the dash as well since tapping on the top of the dash would make it work again. \

my ideas are that there could be a problem in the supply to the fuse box or the fuse box it self.

i did check the fusible links under the hood and found a solid 12.5 volts on both sides of the fusible links and nothing felt hot there 

im wanting to get as much info as i can together for the next time the car comes in so i can trouble shoot it in as short of a time as possible, because they tend to not want to leave their car for very long periods of time. i did sugest they leave it for a couple of days so we could have the time to properly trouble shoot it, but im planning on not having a whole lot of time just in case

 

so can anyone give me some ideas of what i should be looking for to possibly find this short and get it fixed, im thinking first step would be to pull the fuse box and inspect it and make sure nothing is shorting out there on the supply side.

i did visually trace as much wiring as i could under hood, but having a short amount of time and beaing an old ea82 there could be something i missed.

 

[Loyale 2.7 Turbo]

The problem is the Relay for that Headlamp itself, there are Two, one for each Headlamp, but each one ALSO controls other things... all the needed info has been covered in the Following Writeup:

 

Here ~► http://www.ultimatesubaru.org/forum/topic/87523-how-to-swap-the-old-roundie-relays-with-standard-bosch-relays/

 

The Headlamps always receive a permanent Positive (12V+) imput, the so a failing relay which switches grounds, could lead to a Headlamp that stays ON and dim... 

 

Kind Regards.

[Cougar]

Good info from Loyale 2.7 Turbo. Though I think the last sentence is a little mistaken. The relays for the headlights switch power, not ground, to the lights. The switched grounding for the lights passes through the light switch and determine which set of lights gets turned on. The relays are turned on by the switch also by making a ground connection to the relay coils. 

[mikaleda]

cool ill try the head light relay if it comes back, hopefully thats the poblem, a short would be really hard to find in this car

[Loyale 2.7 Turbo]

Yes, I kindly suggest you to start by Switching Relays and see if the Problem goes elsewhere.

 

Good info from Loyale 2.7 Turbo. Though I think the last sentence is a little mistaken. The relays for the headlights switch power, not ground, to the lights. The switched grounding for the lights passes through the light switch and determine which set of lights gets turned on. The relays are turned on by the switch also by making a ground connection to the relay coils. 

 

Don't forget that the Ignition Key controls those relays, that is the reason why if you turn the key to OFF the Headlamps will go OFF, no matter if the Headlamps' Switch is in ON ... that is the reason why I wrote that the Headlamps themselves receives a permanent positive input, which exists every time the ignition key is turned to ON.

 

Kind Regards.

Edited September 21, 2013 by Loyale 2.7 Turbo

[Cougar]

You are correct about the relays turning on with the ignition Loyale 2.7 Turbo. The last sentence in my previous post about the relays turning on with the light switch is incorrect, so "my bad". I had forgotten about that apparently and was just relying on my sometimes faulty memory banks when I made the statement about the coil operation. The headlights do have power going to them via the relays anytime the ignition is turned on. It is the light switch that completes the circuit to ground for the lights in order to turn them on and select which ones are turned on. Thanks for keeping me straight.

[Loyale 2.7 Turbo]

You're Welcome, my Dear Friend.  

 

I Hope that Mikaleda has solved the Problem with Those Headlamps.

 

I've helped many Local EA82 owners to solve similar electrical problems,

 

And always I chose to get rid of the Stock Round Relays and Swap Bosch Standard ones.

 

Kind Regards.

[Gloyale]

The 2 sides of the headlight system are tied toghether through the switch before reaching body ground.

 

So when one side fails to get 12v, the other side light glows dimly because the voltgage on the ground return path is higher than the voltage on the dead side of the circuit.

 

Whenever you see an old subie, or most any older Japanese car, with a very dim light only on one side....it is surely a power supply issue to that circuit.  Either the fuse is blown, or the relay is faulty.

[mikaleda]

yep, they called yesterday and told me that the relay was the culprit and now its working, thanks for the help even though i ended up not needing to fix it.

[Cougar]

Thanks for the update.