Haven't posted here in ages since I've had two 3rd gens collection rust and dust for the past 6 years or so. Anyway the bug bit me again and I'm having some work done....so a little background.

I have an 82 carbed T/A and an 89 Formula 350 with a salvage title I got for $500. I'm currently in the process of having the TPI 350 swapped into my 82. Both cars are intact so I don't have to parts hunt, but I do have questions on the harness.

Is there anything I need to do to have the 82's dash harness work with the 89's engine harness? I searched and found several threads about TBI to TPI and repinning. Is this something I can do also with my 82s carbed dash harness? If so is it the same as doing the TBI to TPI harness?

I would use the 89's dash harness, but there might be some issues there. The guy that sold me the 89 said he had some electrical issues he was never able to track down and although the 89 dash harness is complete as far as I know, he did pull out a lot of wires and there are a few loose wires here and there, so I'm not sure I trust it. He mentioned that that he thought it could be the ECM (if so might need to get a new one, but that is a whole other issue). That and I don't know what's easier, swapping out the whole dash harness or if the option is possible repinning the 82's harness.

Just want to know what options I have, I have a mechanic working on it and they're pretty much done swapping out the drive-train, it's just he wiring issues now.

All help is appreciated thank you.

 

Your 82:

This car had 3 harnesses under the hood. 1 for lights, 1 for the engine, and 1 for the ECM. Rip out the ECM/harness and the engine will still run fine.

82-83 cars used a specific wiper motor. 84+wipers will not properly fit the firewall without modifications. The wiring is thru the ENGINE harness.

82 used the "early" type of headlight motors


Your 89
This car has 2 harnesses under the hood. 1 for lights and 1 for the Engine AND the ECM. 89 used the "late" style headlight motors.


There are MANY wires that are NOT compatable @ the Engine -to- dash connection as well as the ECM -to- Dash connection when mating with an 82 & 89 harness. ( wipers are not compatable, Power distribution is wrong, MANY missing circuits, ect.... )

It that's what you've got,...and you've got to make it work; I'd leave the original Headlight harness and the Engine harness in the 82, and then I'd install the 89 harness as more of a 'stand alone' set-up by adding power and ground ( and anyting else !) where needed. You would need to install a bunch of additional relays and fuses to accomodate this type of build because your 82 doesn't have an electric Fuel Pump, Electric Fan, Injector Fuses, Electric Speedo, or any wiring for that stuff.....

I used a 4th gen fuse/Relay box for the PCM/Harness when I installed an LT1 into my 84. ( had to custom build it, started with a stock 95V6 Box ) I've got to assume that building 1 for a TPI would work just fine too. You could try "re-pinning"; but there is SOooo manny wires missing that your basically building it anyway !




Converting the ENTIRE wiring system - including complete dash swap and all harnesses - to the 89 is another option. There will still be some incompatanility ( wipers still a BIG problem ) but it still seems 'easier' if you've got a complete 89 donor car. I *think* the 89 dash housing will bolt to the 82 body, but SEARCH to be sure !

 

Yeah I think the dashes can just bolt right in, although I like the dash of the 82 better so I'm wondering if just the guts of the dash will bolt in. I looked at the car on Saturday and they have the 89 completely disassembled including the dash. He showed me that the 82's harness was chewed up by the multiple family of mice that likely lived there before (before I took it to the shop you literally couldn't see the engine at all, it was just sticks, hay and mice crap that took me several hours to clean). So I'm not sure how much of the 82s harness is actually usable anymore.

He noticed the wiper motor issue. At this point I'm not sure what they're going to do, he said they can figure it out, but they will have to do some customizing of the harness. I just want to facilitate them and let them know any other pitfalls so they don't hack up anything more than necessary. So not to be repetitive and just for clarification. If for whatever reason they cannot use the 89's dash harness, what is then needed for the 89's engine harness to work with the 82 dash harness?

 

The 82-83 wiper system includes the Wiper motor, ENGINE harness, Dash harness , coulmn wiring and turn stalk. If ANY of those parts are changed to 85+ parts,...... expect headaches.

If ths 89 Engine harness is getting plugged into the 82 Dash harness then - at the minimum -you will need to add:

Relay / Fuse / Wiring for FP

Relay / Fuse / Wiring for Electric fan

Fuses / Wiring for Fuel injectors

Custom Wiring for the Electric Speedo Sensor

Re-Pinning of C100 harness connetor ( At mimnimum: Power distribution )

Heater / Blower connector changed @ Engine-to-heater harness

VATS ByPass



I'm sure that is not a complete list, but it should give you a head-start !