87ChevyR10
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Would getting a HD headlight harness fix all this? The one from LMC looks easy to install.
No headlights
- Thread starter 87ChevyR10
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chengny
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Please don't! Don't trash a (most likely) perfectly good OEM quad headlight harness and then pay money to install inferior aftermarket equipment.
Don't get discouraged - this is easy. I am not bragging, but just trying to keep you optimistic when I say - without hesitation - that if I had 1/2 hour and my Fluke, the problem would be identified. It might not be fixed, but you would at least know what it is.
87ChevyR10
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Ok, Chengny. I checked red wire at switch and it reads 11.79 volts with truck off. I checked driver side lower headlight plug and it gets juice when hi's are on. Also, passenger side hi beam is disconnected due to one of the tabs breaking off. One other thing, the dash hi beam light has quit working from what I can tell.
At the dimmer switch:
When low:
Brown = 11v
Yellow = 11v
Green = 0.066v
When hi:
Brown = 0.045v
Yellow = 11.33v
Green = 11.33v
At the switch:
When low:
White = 0.085v
Red = 11.55v
Green = 11.13v
Yellow = 0
Orange = 0
Black = 0
When hi:
White = 0.079v
Red = 11.33v
Green = 11.15v
Yellow = 11.33v
Orange = 11.33v
Black = 11.33v
At the dimmer switch:
When low:
Brown = 11v
Yellow = 11v
Green = 0.066v
When hi:
Brown = 0.045v
Yellow = 11.33v
Green = 11.33v
At the switch:
When low:
White = 0.085v
Red = 11.55v
Green = 11.13v
Yellow = 0
Orange = 0
Black = 0
When hi:
White = 0.079v
Red = 11.33v
Green = 11.15v
Yellow = 11.33v
Orange = 11.33v
Black = 11.33v
Last edited:
87ChevyR10
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Replaced lower hl's and all 4 work. However, the uppers aren't switching. They are stuck in hi beam mode.
87ChevyR10
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Got a second opinion about the uppers. They seem to be functioning normally.
I'm uncertain what fixed itself; but we'll see how long this holds before the HL's start acting up again.
Using Sylvania XtraVision for all the HL's. The uppers still seem weak on low beam mode. I did go thru and clean up the grounds in the engine bay.
I'll nab a couple night time pics later.
I'm uncertain what fixed itself; but we'll see how long this holds before the HL's start acting up again.
Using Sylvania XtraVision for all the HL's. The uppers still seem weak on low beam mode. I did go thru and clean up the grounds in the engine bay.
I'll nab a couple night time pics later.
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chengny
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However, the uppers aren't switching. They are stuck in hi beam mode.
Got a second opinion about the uppers. They seem to be functioning normally.
Yeah, I know what you mean. The entire description of operation is vague at best and the end of the last sentence (traced in yellow) is downright misleading:
It is difficult to discern the change in intensity from 60 to 40 watt filaments under any circumstances - unless you know it is going to happen and are staring directly at the lamps.
Add to that, the fact; that at the same instant when the uppers are switching from "pretty bright" to "kinda bright", the lowers are transitioning from dark to full illumination.
I'm uncertain what fixed itself; but we'll see how long this holds before the HL's start acting up again.
They didn't fix themselves, you fixed them - by installing a pair of functional sealed beams in the lower bays and using good electrical maintenance practices to correct the issues at the harness/lamp connections.
Unfortunately, I have to agree with you on your feeling that the initial problem still hasn't been addressed. While you do currently have a fully operational headlight system, that won't matter when/if the power supply is lost again. The only difference will be that now you'll have 4 dead headlights rather than just two like before.
Ultimately, this particular problem won't be that hard to diagnose/repair (due to the basic nature of the circuit and the well defined area of any possible causes). But, as anyone who does their own automotive work knows, intermittent electrical problems are the biggest pain in the ass to identify and correct. But don't worry, you'll get this. Keep the faith and try to resist the urge to buy a bunch of expensive new parts and do a shotgun repair.
Got a second opinion about the uppers. They seem to be functioning normally.
Yeah, I know what you mean. The entire description of operation is vague at best and the end of the last sentence (traced in yellow) is downright misleading:
You must be registered for see images attach
It is difficult to discern the change in intensity from 60 to 40 watt filaments under any circumstances - unless you know it is going to happen and are staring directly at the lamps.
Add to that, the fact; that at the same instant when the uppers are switching from "pretty bright" to "kinda bright", the lowers are transitioning from dark to full illumination.
I'm uncertain what fixed itself; but we'll see how long this holds before the HL's start acting up again.
They didn't fix themselves, you fixed them - by installing a pair of functional sealed beams in the lower bays and using good electrical maintenance practices to correct the issues at the harness/lamp connections.
Unfortunately, I have to agree with you on your feeling that the initial problem still hasn't been addressed. While you do currently have a fully operational headlight system, that won't matter when/if the power supply is lost again. The only difference will be that now you'll have 4 dead headlights rather than just two like before.
Ultimately, this particular problem won't be that hard to diagnose/repair (due to the basic nature of the circuit and the well defined area of any possible causes). But, as anyone who does their own automotive work knows, intermittent electrical problems are the biggest pain in the ass to identify and correct. But don't worry, you'll get this. Keep the faith and try to resist the urge to buy a bunch of expensive new parts and do a shotgun repair.
87ChevyR10
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So, it's been almost 4 months and the gremlin came back this morning during my ride home. Went to kick on the highs and nothing. All 4 HL's off. Switched to low, tops are on as usual. I tried a couple more times with same result. About 5 minutes later, I pulled into driveway and they successfully swithed from low to high and back again several times. Go figure...
