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I am trying to track down the cause of dim headlights. The passenger side is dimmer than the drivers side. I have checked and cleaned all connections at the headlights and at the body connections. I checked for voltage and am only getting about 10.5v at the fuses. Can anyone tell me where to look next?

Thanks,Paul
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The ground for the front lights is on the main stud under the dash. That stud is impossible to find until you recognize that it is actually a two-ended stud; the other end is the where the battery ground cable attaches. There are numerous ground wires from all around the front half of the car that converge on this single stud, which is virtually impossible to reach because it's blocked by the heater box, etc.

Chances are, your problems are not caused back there, but rather at the pigtail connection up front. The headlights have a fairly short harness (perhaps a foot long) that then plugs into the main harness; lots of opportunity for corrosion, etc. at either that connection or where the harness plugs
into the back of the headlights. Time spent separating those connections (four in total, two on each side) and thoroughly cleaning them out, is time well-spent indeed.

Some advocate unplugging the ground wire from the connector and grounding it locally to the body, instead of running the ground all the way back around the car to the post in the cabin. Perhaps that's something to consider if simply cleaning the existing connections doesn't work. I did this with my car and it seemed to help a bit.

You might also check the voltage going into and out of the headlight relays. It's possible you have a fault there.

I'm sure others who are more electrically inclined will offer more and better solutions.
Agree with improved grounding locally.

I'll assume the engine is running and the battery is greater than 12VDC.

I would check the voltage at another fuse, say F10

if the problem is dirty switches removing the fuse and checking on the battery side of the the fuses (F1 F5 high and F2 F8 low) should then be the battery voltage.

for trouble shooting, You might want to consider making a heavy wire jumper (#6 / #4) direct from battery to the switch side of the fuses. to determine switches on supply of ground on return

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Last edited by jfb05177
Thanks for the input.
I was able to get up in there and snug up the ground under the dash in the past. Yes, it is a pain to get to. I also cleaned all the connections on the front of the car.
I made a jumper from the battery to the fuses, and the lights got normal brightness, so I guess I have to work back from there.
I checked voltage at the switch and got 12.4v at the red wire. (key off) Turning the lights on, I get 11.7 at the red wire, orange wire, and also at the red/white wire.(engine not running) but only 10.5v at the fuse panel. Would this indicate a poor connection between the switch and the fuse panel on the red wire going to the fuse panel?

I did check voltage on 2 other hot fuses on the panel and they indicated 12.4v(#8 and #9)
quote:
Originally posted by Rocky:
You can solve the problem by running "system power" (fused, of course) to a pair of relays up front, and using the voltage from the switch to control said relays.

Easier said than done, but that is typically how high current circuits ought to be implemented.

Rocky


Not what you stated, but it does remove the current from the switches, but uses the existing fusing

easy to make a drawing, lot harder to pull the wiring !

(I need to still see about adding logic so the lamps don't come on until the doors are open)

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Just a thought. Insrall a double pole relay to the limit switch circuit so that when the limits switch is triggered, the motor stops. On the other circuit, on the separate set of contacts - enable the relay to the lights (that we just installed from my previous thread).

Or buy the PE headlight controller. I would bet it does that too.


Rocky
I took the headlight switch out checked it for resistance. It had quite a bit of resistance on both the parking lights and the headlight circuits. The headlight circuit had over 70 ohms, and would fluctuate with me turning it off and on. I tried spraying some electrical contact cleaner into the switch and operating it,thinking it might clean it up, but then the switch came apart in my hand! Looks like its time for a new one.

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