Upgraded headlight harness

[beastie_3]

I installed my headlight harness today on my 79 K10 and all I have to say is wow. There is a big difference between the stock setup and this kit. For those of you who dont know what it is, it is a wiring harness with two relays that sends power directly from the battery to your headlights instead of from the battery to the headlight switch, then to the headlights. A few years ago I put in HELLA headlights that take H4 bulbs. Even that was a difference but now its amazing. The only thing I didn't like about the harness was that the back of each plug was exposed so I took some black RTV and sealed each one up so water couldn't cause a short. The 12+ wire didn't come with a fuse so I will add one in next time I pop the hood. I will try to get some pictures soon.

[VileZambonie]

Water won't cause a short but most likely high resistance or an open circuit... I just had my students build their own circuits utilizing relays. I had them calculate their source voltage, resistance, current flow and voltage drops. Then they built their circuits and took their meters to measure the dynamic values. I love seeing the results and the amazement. In the average lighting circuit it's not uncommon to see .3V or more of unwanted voltage drops.

[beastie_3]

Relays are so awesome. Wouldn't water contacting the + wire and the - wire on the same plug pop the fuse?

[VileZambonie]

Nope

[87OldYeller]

What kit did you use?

[beastie_3]

I got it from a 73-87 truck parts supplier online, I didn't see a brand on the packaging. Some of it was in Asian writing so......

I think painless makes a kit but it wasn't theirs.

[beastie_3]

OK here are the pictures of the kit. Not much to it really.

This pic shows the relays and the new plug for the passenger side headlight. I have the 12v power wire running under the battery tray and up to the + of the battery. The blue and yellow wire on the left runs across to the driver side headlight. I tilted the radiator and zip tied it to the existing loom already there for the stock headlight, turn signal and horn wiring.


The stock headlight plug is not used and I tucked it away for now and I will move the ground wire later.


Unfortunately I dont have a pic of before and after, I will try to get one soon.