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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: codykrr on January 04, 2013, 10:50:53 pm

Title: heavy duty headlight harness problem...help
Post by: codykrr on January 04, 2013, 10:50:53 pm

ok so I bought the HD harness for my 81 c10.  its got the quads lights. 

I also ordered new headlight housings to accept the h4 bulbs.

I installed the harness as per instruction(which wasnt very clear to begin with). 

problem is, now when I turn on my lows(top lights) the highs(bottoms) are also lit, but very dim. when I turn my highs on the bottoms become bright making my lows dim.

the bottoms(highs) shouldnt be on when my lows are on, and all four should be bright when the brights are on...

anyone have an idea whats going on?

Title: Re: heavy duty headlight harness problem...help
Post by: bd on January 05, 2013, 11:37:29 am

Check the ground connections relative to the battery negative post.

Title: Re: heavy duty headlight harness problem...help
Post by: codykrr on January 05, 2013, 06:47:59 pm

I got it finally. Ends up that H4 bulbs are pinned differently. and you need to pull the metal prongs out of the low beam socket on the new harness and switch them around.

take the prongs out, and put the brown wire on the top slot on the socket.

then move the prong with two green wires to the left slot on the socket.

then finally move the black wire prong to the right slot on the socket.