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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: MyOldScottsdale23 on February 08, 2012, 11:30:48 AM
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I just bought a '85 SierraClassic 4x4 and only one low beam headlight was working. I replaced all 4. Now both low beam or upper lights work but I get no lights when I swith on the high beams. The indicator blue lights come on the dash but no headlights. Any help or suggestions would be greatly appreciated. Thanks in advance!
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my 77 started doing the exact same thing.. i replaced my dimmer switch and light switch. not sure what the solution is, haven't really looked into it much but i would also like to know the solution.
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Check your headlamp grounds. Do the headlamps go dark on highbeam?
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Yes when it goes to switch to the bottom two (high) beams the top two (low) beams go off
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So neither the uppers nor lowers light with highbeam. Sounds like it might be a dimmer switch or connections at the dimmer. Unplug a headlamp and check for power (cause it's easy to get to). As I recall, black is ground, tan is low, and green is high. If green is dead, check the dimmer. If green and tan aren't dead, check the ground.
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So neither the uppers nor lowers light with highbeam. Sounds like it might be a dimmer switch or connections at the dimmer. Unplug a headlamp and check for power (cause it's easy to get to). As I recall, black is ground, tan is low, and green is high. If green is dead, check the dimmer. If green and tan aren't dead, check the ground.
Sounds like it is definitely a problem with a connection, bd is right, start at the lights themselves and check for power, then work your way back to switch and dimmer, this will be the best way to pin point the problem without throwing parts at it.
Keep us informed of what you find.
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So I have noticed that dash lights have been flickering and I have to adjust the dimmer, but the low beams work fine. So I'm confused as to why it would affect the high beams when they work off the wiper/cruise switch on the column.
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So I have noticed that dash lights have been flickering and I have to adjust the dimmer, but the low beams work fine. So I'm confused as to why it would affect the high beams when they work off the wiper/cruise switch on the column.
Mine is a 74, but when I first got it, it had a similar problem. I found I had some faulty grounds and as soon as I fixed the grounds the flicker in my dash lights went away.
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So I have noticed that dash lights have been flickering and I have to adjust the dimmer, but the low beams work fine. So I'm confused as to why it would affect the high beams when they work off the wiper/cruise switch on the column.
Headlights and dash lights are separate circuits. Don't confuse the two. Diagnose them independently.
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I had the same thing basically with my 86 . Make sure the connectors at the lights look good not broken or melted . If you do have to have new switches, I recommend using Delco replacements, the cheaper ones i bought first were not as good and the cheap headlight switch i bought had a faulty circuit breaker inside it (non-servicable). You have good advice in checking all grounds and connections. Good luck and keep after it!
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I had the same thing basically with my 86 . Make sure the connectors at the lights look good not broken or melted . If you do have to have new switches, I recommend using Delco replacements, the cheaper ones i bought first were not as good and the cheap headlight switch i bought had a faulty circuit breaker inside it (non-servicable). You have good advice in checking all grounds and connections. Good luck and keep after it!
here at the chevy dealership all we use is delco parts, its what gm mostly uses now. couldn't agree more, hope you get your problem fixed.