Has anyone installed a Painless wiring kit in a second gen pickup before? How hard and/or time consuming was it?

I've just about had it with the electrical system on my 76. There have always been weird quirks with the charging system, headlights, turn signals, etc. throughout my build, but today was the last straw.

After putting in a 6AL box, the engine turned over a few times before I heard what sounded like a fuse popping and I lost all electric power to anything not coming straight off the battery. I'm getting no power to the fuse panel. I triple checked to make sure that the 6AL box was wired properly, no fuses were blown, and I didn't smell anything burnt or feel anything hot throughout the entire loom. The Sniper EFI is still powering up but no fuel pump priming, headlights don't work, erc.

Short of a fuseable link or ignition switch, Im at a loss as to what could be wrong and am quite frankly at the end of my rope with the factory wiring on that car. At this point I just want to just get it and start over.

Anyone else do this in the past? What kit did you buy? Anything to look out for?

 

Whenever you add all kinds of non factory components, you run the risk of screwing something up.

The old wiring harness is pretty durable. Based on your narrative I would look at your fusable link(s). You should have two within a few inches of the (+) battery post. One for headlights and one for fuse block. Don’t depend on visual inspection, manipulate the wire for any soft areas. If in doubt, replace both.

 

I rewired my '72 second gen with a EZ Wiring 21 circuit kit. Every wire is labeled with where it needs to go but there are things like relays and connectors that you will have to buy.

I used weather pack connectors as much as i could. Otherwise it was quick disconnects.

I switched over to a GM 3 wire Alt, MSD StreetFire ignition box, GM headlight switch. I switched the wiper switch to a fan switch to eliminate the "wash" function.

Everything ends up being your preference as to how you want to wire it and where you put it.

 

I suspected a fuseable link as well. I believe there is a heavy white and a heavy red/blue wire off the positive terminal. The heavy red/blue has power all the way to the headlight relay so I'm guessing the link in the white popped.

The issue is that this is actually for a 1976 Chinook camper that I'll be adding a lot of powered accessories to and modernizing for better reliability and economy (it's already got EFI.) So expanding the amount of circuts I have and modernizing the fuse block would be worth it in the long run. Just trying to get a feel if anyone has done this in the past.

@jetas - I think that is the play here. Given that I already have a Sniper 2300 system on it, the MSD box, electric fans, and am planning on a lot of comfort items for the interior (heated seats, back up camera, cruise, vintage air kit, etc.) the factory fuse setup is already starting to not cut it.

Assuming you just pulled the main loom and wired everything up from there using existing routing from the factory? Am fine putting in the work if it means reliable and easily replaceable modern components.

 

Most of these harnesses seem to be based on a GM style harness. There are A LOT of diagrams for most of GM stuff and can be easy to follow. And a lot of the switches can be simplified. These trucks mostly run + thru the wiring and things ground thru their mounting points. Do you have emissions testing where you live?

my suggestion, run one harness to run the truck. Swap in a higher amp alternator. Run two batteries, one to run the truck and the other a deep cycle battery to run light camper accessories w/o a generator. Run a separate fuse block(off the deep cycle battery) for the camper portion. This way you can isolate issues and simplify the wiring

 

Thanks Jetas. No emissions testing, thankfully. So hopefully that simplifies a potential install a bit.

As for separating the harnesses, that is the plan. The truck has a 55A alternator in it currently and I sourced a second battery box for under the hood. I plan on running the camper side off a deep cycle fed by a batter isolator to keep the truck and the camper electric separate.

Engine Bay with secondary Battery Box


Upgrading the harness on the truck has been on my mind since I bought it, as to your point, it would simplify things but also make parts easier to source. I plan on using the rig quite extensively and will ultimately end up in some pretty remote areas. I'd like to be able to stop at a local parts store to pickup parts when anything breaks rather than having to build a time machine.

And any tips for integrating the updated harness into the factory? Anything that was tricky when you were doing the install?

 

I'll tell you this much. Only factory pieces of wiring left on my truck at the pig tails coming off the tail lights. Literally every other wire is new.

 

Confirms what I was already thinking. At this point it's worth the work if I don't have to deal with the factory wiring anymore. Thanks all.

 

Honestly IF your current harness isn't all fried, it would probably be easier to recreate the factory harness. The densest part of the harness is the dash and engine.

Depinning is easy, and you can just lay the harness out or pin it to a wall and replace everything one wire at a time and everything will work fine

 

I guess that is an option too! I'm less concerned with the cost of a new harness than I am with having it be totally reliable and easy to find parts for. Im this far into the thing already haha. I'll probably just end up going with a Painless kit and calling it good.

To your point, the only thing Im slightly apprehensive about is the gauge cluster / rest of the dash. There is a lot going on there and isnt a great 1-1 connection.

 

Here is the pinout for the gauge cluster on a 72 second gen. Its fairly simple. Most of it should be similar on the newer truck side from the temp gauge. Early trucks didnt have it. The connector itself is actually numbered (atleast mine was) got rid of the OE gauges in favor of Speedhut gauges

 

Incredible. Thank you! Got next months project all lined up now.

 

@jetas - Quick follow up question on this. Did your truck have a clutch safety switch? If not, did you wire one in? And if you did, how did you mount it on the clutch pedal bracket?

Mine currently does not have one and I'd like to add one in but am having trouble visualizing how I can mount one.

 

Mine didn't have one and i didn't add it in. Avoided running extra wires as much as possible. Also I've worked with a lot of new cars with push to start and i force learned the habit of always starting cars with my foot on the brake.

as far as mounting the NSS, just go to a JY and pull one off a newer truck. I assume it completes the circuit, so purple starter wire from ign switch to NSS to starter. Just test the continuity of the switch to see the function