Replacing wiring harness for 91 Blazer

[tj 413]

I searched through the threads for some info on replacing the wiring harness for the truck. Didn't find alot but saw comments on not messing with something if it isn't broke. I definitely have an issue with the wiring for my power windows when I press the drivers side ,the passenger window sometimes goes down. I had to take the door panel off and fiddle with the wiring to get it back up once. Its a bit of a rats nest under the dash but haven't really dug too deep yet.

I think I would rather fix it all at once than bits and pieces at a time as potential issues pop up for the 35 year old wiring.

I've got a guy whose gonna take a look at it to see if it's worth fixing up the existing harness and potential issues.

That being said, what's the best complete wiring harness to use?

 

[Blue85]

The PW/PL harness is a separate assembly from the main cab wiring, because it was an optional feature. There is a harness in each door and another that runs the width of the dash. It plugs into the fuse block, so the whole thing can be easily swapped. Somewhere in the late 80's, they changed some of the connectors, so you'll need to stick to later harnesses. I determined it was probably for the 1988 model year: https://ck5.com/forums/threads/80s-...-housing-etc-fire-damage.348502/#post-4361783.

Are you saying that pushing one button moves the other window, or just that operation is intermittent? The biggest chance of failure is in the switches themselves, or the motors, but sometimes the connector contacts get crusty. You will also find threads here about upgrading the window performance with relays. It can be DIY or there are kits available, but either way, they can work fine with marginal old switches.

 

[tj 413]

Yea, I know LMC sells an American Auto wire generic 21 circuit kit which includes the PW/PD wiring. I'm thinking it makes the most sense to buy the entire wiring harness offered by LMC even if I only do the door wiring first. The door switches are new, I cleaned the wiring plug in and sprayed the electronics luuube prior to hooking them up.


I dont want to have to keep going in and out of tbe doors for additional potential issues...Doors have new glass, new actuators, new switches. I have the full wiring kit with relays from K5 Squared to be installed, still need to buy a new rear window motor. Should I get new door window motors although the actually go up and down with no issues.

 

[Blue85]

If you already bought the relay harness, why not try it? Getting a whole cab wiring kit will be a lot more work and bring additional questions.

New switches? From where?

Also, please respond so we can help.

Are you saying that pushing one button moves the other window, or just that operation is intermittent?

 

[tj 413]

The door switches came LMC (probably made in China) they work on and off correctly. I haven't used them for weeks as I dent have to have to deal with a window that won't go up in the winter.

I think eventually the cab wiring will all need to be done at some point being 35 years old, also the cost of parts continues to rise so I would rathr sit on it, then pay double down the road.