Cleaning up / moving wiring, anyone done it before?

Hi guys,

I didn't know if anyone had relocated anything like the sensors around the MAP, or moving the coilpack etc away from their normal location.

A friend and I are planning on doing some wiring cleanup and I wanted to see if you guys had any pictures of what you have going on now. Thanks in advance!

Well, we actually got started last night.

Closest approximation I could get to the normal hole that the main harness goes through at the firewall was about 2 1/8". So we did a quick trip to Lowe's to get a hole saw and got to work. The initial area I wanted to drill through was a little too high up, and everything would've been just as high as the ign. module, etc. So we ended up lowering it a little bit, the hole sorta looks like a circle with horns, some cleanup will be needed there of course.

What you can see through the hole is the back of the intake/top of the block, and a wire that needs moved.

All the cumbersome hard plastic pieces have been removed, and we tried not to destroy them any more than they already were. :biggrin:


Essentially I'm going to go with a plan I saw a long time ago that involved routing a lot of the wires through the bottom portion of the intake. Doing this, we should be able to eliminate a LOT of excess wiring, especially routing the main harness through where we are.
Well, my friend that's helping me is feeling extra generous and motivated; so he's going to help me do as much of a wire tuck job as we can manage. So far we've eliminated most of the A/C, blower, wiper motor, fan relays and other similar items (last picture). When I'm not busy with school I've been making labels for all the wires to make our job easier. It looks like we may re-locate the fuse-block and C100 bulkhead to somewhere a little more knuckle friendly if we get a chance, probably inside the passenger compartment.



Made a little progress over the weekend. My friend Matt and I (Matt is the one responsible for everything good that is going on with this wiring project. I'm labeling wires and learning like a good boy) pulled the dash out, and got to chopping up some wires.

I'm in over my head...

The dash out, and sitting inside, where car parts should be!

Chop chop!

Hopefully this continues to go as smoothly as I'm wishing.

Is anyone knowledgeable about the wiring in the dash? I'd like to eliminate any of that that is unnecessary if at all possible. (I'm keeping cruise control and the aftermarket stereo, and have a digital dash).

We decided it would fit in with the overall goal of the project to re-locate the C100 bulkhead connector as well as the MAP bracket to inside the cabin, wherever we can find room. I haven't yet decided whether I'll put the electric fans on a switch, or just re-use the temperature switch that I used before. Let me know what you think.

As an aside, I still have my Hot-air wiring harness with the Hobbs-switch, while the wiring harness I'm using is an analog. Can/Should I just swap out the MAP for the Hobb's? Or should I just install the Hobb's along with the MAP, and use the Hobb's for my dash lighting, while the MAP goes to the ECU?

Lots of questions, but hey, I'm having fun so far.
Discovered an issue that may have been keeping my car from running halfway decent at idle.

While tracing all the ECM wires, I discovered the Air Charge Temp Input (C11 I think) was running to the ground at the back of the passenger side head! I went out and got the sensor, so hopefully that helps remedy the problem. Hopefully should have some updates this weekend!
Finally got started putting all the wiring back in on Saturday. Here's where we ended up. We'll be pulling everything back out to get it to reasonable length as well. With as much wiring as was eliminated, the 2 1/8" hole drilled is WAY too big, with the exception of MAF and IAT, all the regular sensors are running through where they will. The charcoal canister and cruise are eliminated, and I'm still searching for a reasonable method to move the canister venting toward the rear of the car. Let me know if you have any suggestions on that one!

Regarding the ECM: Since this car has had the A/C controls eliminated, we'll be mounting it behind where those controls used to be, if it's not too terribly difficult. Which is nice, because the entrance to the engine bay is about 4 inches behind that! I'll have to make sure I leave enough space for a USB cable. I'll probably need to get a 90 degree USB adapter and make a faceplate for it.

Also, since the lady is out of town this week, I should definitely have time to finally make my camera mount for the passenger seat.

Here is 90% of the wiring that will be still running into the engine bay.

Before it was taped, all running through the bottom of the intake (IAC was a little difficult to fit through, but we did it).

Where they pop back out.

Driver's side with almost nothing on it. All wiring (and maybe the hood release) will hopefully be hidden under that front 1/4 panel, if it's feasible.

More to come next weekend.
In wich direction do the AC and cruise control wires go ??
Towards the drivers side bulkhead
Towards the ECM on the passenger side
Cruise control wires should be wrapped around a vacuum hose and run to the firewall, near bulkhead. If you look under your dash (might be hard to see with the steering column in the way), there is a white fitting with a vacuum hose on it, that's the CC module, trace that back to the firewall and you'll see right where it goes in.

AC is a little more tricky, those MF'ers go ALL OVER THE PLACE. If I remember right, quite a few of them are tangled near the bulkhead (all power wires I believe), with the AC clutch control going to the ECM. Hope that helps!

Someone correct me if I'm wrong please!
My buddy Matt came back over and started re-assembling the harness. This guy is a wiring ninja. Let me know what you think so far. It's about 80% done. We still need to connect some of the more important stuff (MAF, Air Temp, gauges). But you should be able to get the gist of it from here. He estimates another 3 weeks and this baby should be on the road. 3 more weeks? That's right after finals is over! Perfect timing! :D:D:D

It begins:

Wrapping the completed portion, looking fancy:

Getting some soldering done:

Missing a few wires, but they'll be running an alternate path, since they are so far away from the rest of the wiring:

Comparison to an unmodified hot-air harness (~11ft vs ~4ft):


God loves Buicks!
I'm going to make a couple of suggestions. It's good that you're soldering it but make sure you're using rosin core (or solid) wire and make sure ALL the flux is off the connection before you seal any joints. Also, make sure you're doing environmental splices. By that I mean don't just shrink tube it, make sure it's impervious to water. The last thing you want is water getting inside the insulation of the wires! One last thing I would suggest is that you don't use electrical tape. It'll just end up being either a goey nasty mess or drying up and falling apart. If you don't have a place to make a good loom for it then use lacing cord and spot tie it or use lacing cord to hold some split loom together. I don't know if you're doing any of these things but I figured it wouldn't hurt to post it just in case someone else reading this thread doesn't know about this stuff. Good job on your project.


New Member
Thanks for the suggestions! I'm the one working on Dan's harness for him and this is my first Buick harness and actual wire tuck. I've done a few harness conversions in the past for motorswaps in imports and quiet a few wiring jobs on motorcycles (race conversions mostly) so I understand where you're coming from with the environmental splices.
The good news is that the only splices that really will be at any risk will be the cam and crank angle sensors where they splice into the ignition control module. I had considered pin pulling those wires on that connector and redoing the pins, then repinning it. The rest of the wiring will be on the inside under dash area behind where the factory climate control system. This car has deleted heat/AC so there is a ton of room there under the dash. I'm still going to make sure everything is just so-so just incase of any issues, but the wiring itself will pass through an RTV sealed bulkhead via the hole Dan put in the firewall. For now the electrical tape is holding it together while we test fit everything and make sure that it's all to exact length. End plans are to loom it together and make it look pretty for the little bit that you can see. There is still quiet a bit of work to do as far as the wiring is concerned with rerouting and hiding the headlight harness and redoing a good bit of the under dash wiring.

If you have any questions/comments feel free to ask and I'm still open to any suggestions at all. I'm still young and I'm sure I have a lot to learn.

'84 your dash looks like it will turn out great if you're going for a look like the pictures I saw in the other threads you posted. That dash looks like a cockpit almost with all the gauges layed out like that. Only thing I could suggest would be to get wiring diagrams of each harness you're using and do pinouts to make 100% certain that everything matches up to what you're doing. I know that seems like common sense, but I've seen it skipped over for some reason.


Active Member
Wow that’s allot of work My car is at the body shop but when it gets back I will take pics for you guys, Last year I hid most my wiring. I kept all my accessories like AC heat and cruz but no EGR stuff so can’t help you there. What I did to hide everything was first pull all the wiring on the driver side of the car from around the front of the car and set it aside then if you look under the relays on the driver side fender you will see a ¾ in hole. I drilled that hole out to 1 ¼ and used a Chevy oil fill grommet from back when they had the intake oil fill. I then added about 1 foot to the cruz wiring and vacuum line. Then I added about 3ft to the fan and MAF wiring Then I added all of that to the wire loom for the head lights then I ran all the wiring for the driver side of the car in the fender by putting it in that whole.
What was left I took out of the loom from around the valve cover and ran it under the intake manifold and to the front of the engine to everything it needed to go to. Now there is no wiring on my driver side fender and no wiring down the driver side of the engine. I didn’t mess with the passenger side at all. I also ran the wiring that is over the top of the PM under it and pulled that wire tab off the car. I also moved all wiring going in to the car in to one hole and did away with the hole to the left of the steering shaft.


New Member
Awesome.. That is almost exactly what I was planning on doing with his headlight/fan wiring. We actually moved the C100 connector to inside the car under the dash and I've been looking for something that will fit in that hole in order to block it without welding new metal, smoothing, and deleting the hole completely. The tenative plan I had was to run it under the fender, out, and in through the old C100 hole, then make a small barrier blocking view of the wiring there to mount the fuel pressure gauge.
Everything on the passenger side of the car is now either inside under the dash or deleted. We're relocating the battery to the trunk and making a power block for the wiring that went to the battery to goto. In the trunk there will be a circut breaker on the positive side at the very least, though it is possible the negative side will end up with one as well.