What have you done to your square lately??

[da_raabi]

Ugh. Dude wiring harness swaps is a LOT of work. Do a TON of research and be very prepared for an incredibly time consuming project. Good luck!

 

[HotRodPC]

You sure it has a Th400? If its the original trans, it should be a 700r4, or someone may have swapped in a Th350 which is pretty common to do. Very well could have swapped to a Th400 too, but the Th350 intermediate 9in shaft is pretty much just an even swap and add a vac line, so that's what most will do. With Th400, need to wire a kickdown switch, change the trans mount and crossmember location and have the driveshaft worked on to fit.

 

[Stewzer55]

It could have been a TH350C too.

 

[HotRodPC]

It could have been a TH350C too.

True, but for conversion sake, it's the same as a Th350.

 

[t1xj]

I'll try to get my dad to take a pic of the glove box codes, as well as the trans oil pan. i based my th400 statement off my memory of what the trans oil pan looked like when i got under the truck briefly. unless i am mis-remembering. it didn't appear to be the 700r4 or th350. but i could be wrong as i wasn't specifically looking for the shape of it at the time, i was more looking for rust.

I've been reading for days about wiring harnesses, the one answer i can't find out is whether i can use the stock gauges with a harness like the painless engine harness or if i'll have to use aftermarket.

 

[HotRodPC]

Those painless harnesses are good, but expensive, and then when you go to them, you're not OEM any longer. I prefer to find good used OEM harnesses off of donor trucks like at a DIY parts yard. I can't help you with a harness. I have one for an 81, and that one is wiper switch on the dash and bright light switch on the floor. You need a harness with a multifuncion switch like the 84-86 and maybe even thru 89 for the hanress you need. I'm just not sure if the interior harness is different for the TBI trucks. I know it's different for underhood. Then the 91 harness I have has different connections and is for a Burb so it has alot more **** to it since Burbs have more options than pick ups, like more lights, doors, rear air and defrost etc.

If you can find a harness off an 84-86 I'd say it should very painless and should be an OEM swap.

 

[t1xj]

If I can find a good oem harness I'll use it but I haven't been able to find one. I've called several junk yards and have been searching craigslist. I'm already not original (motor) so I'm not really worried about that quite as much. Just want to get it in god running condition, then assess the trans swap and bodywork idea.


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[HotRodPC]

Exactly what harness do you need? Do you need just the under hood harness? Or the cab harness? Or the rear harness for taillights, and fuel senders? You mention the engine wires weren't tidy, so maybe you just need that harness. Let me know and I'll fire up a wanted ad for that harness. Guys scrap these trucks sometimes and might be able to save a harness for you. You can't post it yet cuz you're new and haven't hit the 50 post minimum for Classifieds section.

 

[ScottyB]

From a newbie point of view...

The downside I see to using a donor harness is that you inherit a 30 year old harness that may include brittle wires prone to breaking once moved. Granted, that 'shouldn't' be the case but how sure can you be when you don't know the history on the donor.

Just my two cents.

 

[HotRodPC]

From a newbie point of view...

The downside I see to using a donor harness is that you inherit a 30 year old harness that may include brittle wires prone to breaking once moved. Granted, that 'shouldn't' be the case but how sure can you be when you don't know the history on the donor.

Just my two cents.

Anything is possible, but most of the harnesses I've seen for these trucks in wrecking yards are still pliable and flexible. They may be butchered up, burnt, spliced and not worth a **** due to idiots, but as far as age, I think they hold up well. Now I have seen the black plastic protective wire coil get brittle and flake off to nothing, but the wire inside is just fine. Put new plastic covering on, and good as new again. With copper as expensive as it is now, I'd imagine newer cars wiring might not last as long.

 

[ScottyB]

Fair enough.

 

[t1xj]

Just under the hood as far as I know. I wish I had my phone on me when I was with the truck this weekend is could have taken pictures of the problem areas


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[robert8096]

I'll try to get my dad to take a pic of the glove box codes, as well as the trans oil pan. i based my th400 statement off my memory of what the trans oil pan looked like when i got under the truck briefly. unless i am mis-remembering. it didn't appear to be the 700r4 or th350. but i could be wrong as i wasn't specifically looking for the shape of it at the time, i was more looking for rust.

I've been reading for days about wiring harnesses, the one answer i can't find out is whether i can use the stock gauges with a harness like the painless engine harness or if i'll have to use aftermarket.

Painless factory harness will use stock gauges. What it don't cover is the power windows/locks harness.

http://www.painlessperformance.com/webcatalog/lv.php?sl=10205

From the site above.

It features a factory style bulkhead connector and has many of the factory connectors already installed on the harness out of the box. Including: the headlight connectors & switch, dimmer switch, wiper motor, ignition switch, blower motor & switch, blower resistor, and instrument cluster.

Install manual link also on the above page.

It's not cheep around 650 bucks.

 

[t1xj]

I thought I had read they will work with power windows/locks but I could be mistaken. No real decisions have been made, still searching for an OEM harness. Although(to throw a wrench in the mix) I did buy a 454/sm465 mostly complete swap(minus standard cab hump and wire harness) for a good deal yesterday. Thinking about whether to split that or throw it in as is and sell chromed up 350 that is in it.

 

[silverscottsk10]

I'll take the 454/sm465 lol