Headlight Issue
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Joined: Aug 2013
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Headlight Issue
Need some help with a headlight issue on my 89. Noticed last night when I was driving it home from the exhaust shop that my high beam indicator glowed slightly even with the low beams on. I got out and checked the lights and the left headlight was very dim. I checked the headlight plug and I have 12.3V on the high beam lead but only 4.85V on the low beam side. I was initially thinking bad ground but if that were the case I would think it would show across both leads ?? If I unplug the left side connector, the faintly glowing high beam indicator goes out but works properly when on high beam. Thoughts?
Thanks
Robby
Thanks
Robby
Team Owner
Joined: Sep 2003
Posts: 25,381
Likes: 2,736
I would think you start with just a confirmation of the TAN and LT GREEN at the connector. Disconnect both LH/RH and with your DMM, VM you want appropriate values at TAN when dimmer on LOW and appropriate values at LT GREEN with dimmer on HIGH. You check both of these with the FOG LIGHT switch in the OFF position. That confirms there's no issues HL switch, dimmer and wiring to the front of car. If you have errors or issues then an issue is isolated.
To check the lamps and grounds I believe it's maybe important to know what lamps are used and how the FOGS are wired. Are the lamps basic sealed beams with incandescent standard FOGS or has either/both been modified or changed. An '89 I believe has the FOGS grounded through the HI filament so if this was bypassed to have "on demand" FOGS then the diagnostics change.
The "first-responder" mentioned fusible links, battery connections or battery - those are just a WAG I'd say. There's no fusible link and you were driving the car so ...........................
To check the lamps and grounds I believe it's maybe important to know what lamps are used and how the FOGS are wired. Are the lamps basic sealed beams with incandescent standard FOGS or has either/both been modified or changed. An '89 I believe has the FOGS grounded through the HI filament so if this was bypassed to have "on demand" FOGS then the diagnostics change.
The "first-responder" mentioned fusible links, battery connections or battery - those are just a WAG I'd say. There's no fusible link and you were driving the car so ...........................
