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#1 |
Senior Member
![]() Join Date: Jul 2009
Location: Exeter, NH
Posts: 790
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High Beam issue
I went on vacation for 2 weeks and left my 1969 GMC C-1500 truck sitting in my garage. I went to open the hood and it was hard and wouldn't stay up, one of the lift cylinders on my billet hinges stopped working. Ok I called and have two new ones coming. Then yesterday I was checking my lights and turned on the headlights low bean and lights all worked hit the dimmer switch for high beam and low beam went out and the high beam didn't come on ! I bought a new dimmer switch no change. I have been chasing wires from the bulkhead to everywhere they are supposed to be. Nothing. The light switch was new 5 years ago and everything worked 2 weeks ago !!! Where do I go next? I think my truck may be mad at me.
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#2 |
Registered User
Join Date: Dec 2017
Location: Elkhart, Texas
Posts: 1,708
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Re: High Beam issue
First step is to round up three important tools (1)test light or volt meter, (2) wiring diagram, (3) A well-fitting "do not assume" hat.. Guessing and throwing parts, and hoping something sticks is not a proper repair method..
Voltage comes from the headlight switch to the dimmer switch through the light blue wire.. Since you have low beams, that circuit is working.. At he dimmer switch, you should have voltage alternating as you "flip" the dimmer switch, on the light green and tan wires. If you don't, the switch is bad.. If you have voltage on both wires, check for continuity on both these wires at the firewall connector, Again, alternating on each of these wires on both sides of this connector. If voltage is present on both wires on both sides of the connector, continue checking the wires inside the harness for breaks.. Check for voltage on these wires at the plug at the headlight bulbs... |
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#3 |
State of Confusion!
![]() ![]() Join Date: Jul 2002
Location: Gulfport, MS USA
Posts: 46,900
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Re: High Beam issue
Last 4-eyed truck I had had same issue, turns out both hi-beam bulbs were dead.
__________________
Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! |
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#4 |
Senior Member
![]() Join Date: Jul 2009
Location: Exeter, NH
Posts: 790
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Re: High Beam issue
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#5 |
Senior Member
![]() Join Date: Jul 2009
Location: Exeter, NH
Posts: 790
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Re: High Beam issue
Did all that I am getting a new relay later this afternoon.
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#6 |
Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,338
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Re: High Beam issue
Wiggle the plug at the bulbs.
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71 C-20 07 Magnum RT AWD |
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#7 |
Senior Member
![]() Join Date: Jul 2009
Location: Exeter, NH
Posts: 790
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Re: High Beam issue
did that it was all new American wire when I built it. It was working fine when I parked it two weeks ago.
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#8 |
Registered User
Join Date: Oct 2005
Location: Overland Park, Ks.
Posts: 5,217
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Re: High Beam issue
Check the plug at the dimmer switch. It is well known to get corroded. It is in a poor environment
George. |
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#9 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,643
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Re: High Beam issue
I must have missed something, didn't think these trucks had headlamp relays. If relays were added (great idea, btw) then yeah, that could be the culprit.
I would troubleshoot with a VOM or at least a test light before throwing a new relay at it, though.
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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