Headlights shutting off

[winford hackworth]

I've been researching this and just about all I've seen is that the wiring harness is what's going bad on these and can't handle the load. Does anybody know where I can purchase a heavy duty one for replacement at a reasonable price.

 

[magimerlin]

There's a few places if you type in gmt400 headlight harness upgrade is search engines(google,mozilla,etc)

Otherwise you can make your own pretty easy and use the factory power wires to trigger the relays...

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[winford hackworth]

There's a few places if you type in gmt400 headlight harness upgrade is search engines(google,mozilla,etc)

Otherwise you can make your own pretty easy and use the factory power wires to trigger the relays...

Sent from my SAMSUNG-SM-G891A using Tapatalk

Ok thanks alot for the info. I will search for it first

 

[df2x4]

You can send a message to @gmachinz if you like, he custom makes heavy duty headlight harnesses (among other things) for these trucks.

 

[winford hackworth]

You can send a message to @gmachinz if you like, he custom makes heavy duty headlight harnesses (among other things) for these trucks.

ok thanks

 

[gmachinz]

This is my upgrade kit-I don't have any ready to ship right now (I sell out every time I have several built) but I can have one ready to within 2 weeks. I try to maintain a regualr harness building schedule and custom harness builds can take some time-that and I am actively building projects both mine as well as several people in our family so time is always tight lol. Drop me a line if you're interested-cost for the plug n play 4-HI as you see in the pic is $146 shipped.

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[sctrailrider]

When he says 2 weeks he really means 2 months, I payed 250.$ for my head light harness, waited 4 weeks, when the harness arrived it wasn't complete, was missing the all on & relay part, that was 2 weeks ago and he won't answer messages... stated 2 weeks ago he would open a box and pull out the relay harness portion and send it right out... 2 weeks ago and still nothing...

Jaibin, I need my harness so I can use the truck....

 

[eyesi]

or you can disconnect and clean and tighten all harness terminals, all time when there is a bad electrical contact, every time you will find burn colored/molten plastic connector/s , .

 

[GMCTRUCKS]

It could be your headlight switch mine high beam would shut off it was the switch

 

[gmachinz]

The factory headlight switch has a built-in ballast so IF you were to swap out for higher powered headlight bulbs and/or NEW stock type bulbs, with age that headlight switch can increase resistance even further creating more heat and can lead to failure altogether. GM just never seemed to embrace the relayed headlight idea until much later and they still used skimpy wiring. Also, the 280-series headlight connectors attracts a lot of corrosion and junk so it may also help to remove the terminals, clean them-the connectors and squeeze a bit of dielectric grease inside the connector before re-inserting the terminals to help keep moisture out.