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| | | | Joined: Sep 2017 Posts: 19 New Guy | | New Guy Joined: Sep 2017 Posts: 19 | Hey guys,
I have been pulling some late nights on my truck, the other day I noticed that the headlights would randomly turn off and then on again with no real pattern. When they are getting power the beam seems to be strong, but it will just randomly go on and off, obviously not ideal for driving at night. Anyone have anything like this before?
The dash lights stay on strong when this is happening, and I have a full battery. Does this seem like a ground issue? Also it is both headlights at the same time not just one side or the other. I believe when the headlights are out the tail lights stay lit , but not 100 on that.
Any ideas appreciated for troubleshooting. Love these old trucks! | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Since you live in the rust belt, disassemble and clean all wire and switch terminals. Reassemble with some dielectric grease.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Apr 2005 Posts: 7,440 Bolter | | Bolter Joined: Apr 2005 Posts: 7,440 | Be sure to clean the contacts on the floor mounted dimmer switch!ðŸ›
Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
Support those brave men/women who stand the "Thin Blue Line"! Hug a cop!
USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
| | | | | Joined: Sep 2017 Posts: 19 New Guy | | New Guy Joined: Sep 2017 Posts: 19 | Good idea guys, I think cleaning the terminals is my first line of duty. Hopefully that will be the culprit. | | | | | Joined: Mar 2017 Posts: 326 'Bolter | | 'Bolter Joined: Mar 2017 Posts: 326 | I had something similar in my 69 mustang that ended up being the switch. I found that turning the headlights off then back on always worked.
Good luck.
1956 Chevy 3200, 235 w/3 speed
| | | | | Joined: Dec 2015 Posts: 2,063 Big Bolt Forum Moderator | | Big Bolt Forum Moderator Joined: Dec 2015 Posts: 2,063 | if just the headlights are affected, and not tail or instrument lights, as Martin said, check the dimmer switch. Next I would check the headlight switch although, instead of a circuit breaker, there was a short fuse in the switch
(as seen here https://www.americanclassic.com/1955-59-Headlamp-Switch/productinfo/53%2D112/ ).
I am not sure if the fuse affects all lights or just headlights. Normally, a fuse would just quit working, but I would check it out anyway. | | | | | Joined: Aug 2009 Posts: 152 'Bolter | | 'Bolter Joined: Aug 2009 Posts: 152 | I had a similar occurrence on my '59. The head lights on one side would tune off at random times. The culprit was a loose fitting connector behind the headlight bucket; it would vibrate loose just enough to interrupt the circuit. Hope this helps.
Oldbolter
1959 Apache 3800 dually flat bed/dump with 261
1956 3800 dually flat bed/dump with 235
1957 3600 flat bed, 350 engine, 700R4, PS, disc brakes, 14 bolt rear with 4.11 gears
| | | | | Joined: Mar 2005 Posts: 1,636 'Bolter | | 'Bolter Joined: Mar 2005 Posts: 1,636 | If both headlights are going out and coming back on but all the others are working, as already suggested check the dimmer switch. If you are using halogen bulbs then you might want to consider installing relays to the bulbs to take the load off the dimmer switch and headlight switch. | | |
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