Painless rewiring of 1975 D100

Hey everyone, just wanted to announce that I've begun re-wiring my 1975 D100 long-bed with a Painless 12 Circuit Universal Mopar Muscle Car Harness (part #10127 on their site). I'm mostly following 75 Power Wagon's example, though my truck's in rougher shape to start.

So far, the truck had a new tranny and engine when we got it in early '06. Since, we added a nice Edelbrock intake and 4-barrel carb, and new brakes. With this wiring job, it'll be basically a new vehicle!

I'll start July 5th with my father- and grandfather-in-law -- wish me luck, guys!

The dash is bleeding old, dying wires:


Old fusebox with the previous owners' hard-wiring. Frightening.


I took apart the dash to find out why I couldn't get dash lights. I found more than a few problems; this wiring is a time bomb. I wasn't comforted by what this board said about the Ammeter, either.


The old, cracked wiring in the engine bay.


The dreaded firewall connector.


The truck with the neverending bed.

Good luck.Keep us posted.Lots of pics would be nice.

Nice Rig Looks like you got yourself a good project........I had the same truck (76 Longbed)and it is now a short utiline bed. If you want to shorten the frame and install a shortbed let me know and I can give you a step by step rundown on what's involved, Although that longbed does come in handy from time to time.

Ron

Saweet dude. Definitely keep us posted. Might motivate me to get going on mine

nice! i just talked to you... and it sounds like this will be a great improvement..

I'm curious as to whether we would be better off upgrading our harnesses with the mopar muscle car harness or the universal truck harness... but, painless it definately the way to go.

Originally Posted by Speed Dragon

Saweet dude. Definitely keep us posted. Might motivate me to get going on mine

ShitSpeed.... The 'motivation' is always there.... It's just 'time and $$' isn't it??

Hey there impulse! Welcome to The Brotherhood!!

Yes you are correct... Ampmeter is a MAJOR prob with our old rigs. Fix not that bad though...

Bulkhead connector (firewall) Is not as bad as you may think, as long as it already hasn't been cooked/fried/melted by our friend, the crappy ampmeter... Even that can be cleaned/cured/fixed.....

If your dash/inst circuit board is in terrible shape, lemme know... I've brought more than a few of these 'back from the dead'...

Thanks, guys.

bherder, 75 Power Wagon and I briefly discussed the instrument panel; we seem to think that the Painless setup should match it without issues. Do you agree? Or will I need to get the Painless dash kit and some new gauges?

Originally Posted by bherder

Shit Speed.... The 'motivation' is always there.... It's just 'time and $$' isn't it??

Yeah you're right. If I had 10 mil and no job I'd have quite a few kick-azz cars

Originally Posted by impulsenine

Thanks, guys.

bherder, 75 Power Wagon and I briefly discussed the instrument panel; we seem to think that the Painless setup should match it without issues. Do you agree? Or will I need to get the Painless dash kit and some new gauges?

I've never done a 'painless' retro fit, so I have no idea...

What do these four things do? It's the left-hand side of the truck, right behind the battery (whose positive lead is that huge black wire in the lower-right corner).

I know one's a voltage regulator (#2 or #4), and #1 is a ballast resistor. But I can't make a positive ID for sure. #4 seems to be the power source (as the positive battery connects to it), but #2 looks more ... regulatorish. And I haven't a clue what #3 is.

Is the ballast resistor for regulating the starter's electricity? That's what Wiki said...

Anyway, thanks in advance for your :



If needed, I can post some closeups of each component.

#1 is your ballast resister... #2 is your ignition module... #4 is your starter solenoid... I do not know what #3 is... it looks like soem sort of relay, but im not really sure... never seen one...

The ballast resistor regulates the voltage for the ignition module.... the ignition module, is well, the ignition module... kinda self explanatory... these two parts are common problems on our trucks... and the starter solenoid is just a huge relay that gives power to the starter when you turn the key...

someone explain what #3 is, because im curious now too..

It doesn't look like anything 'Mopar' I've ever seen.... Relay? Maybe, but I see only two (Maybe 3 ) wires hooked to it. There looks to be a yellow wire running up to it, but I cant tell for sure. I see there is one wire that's hooked up to 12v 24-7 with what appears to be a fuseholder ... Can't quite tell, even after blowing the pic up....

Eh, who knows who did what in the last 30 years.....

Looks a lot like my old horn relay.....

Yeah the extra relay isn't factory. The rest is, #1 ballast resistor, #2 Ignition module, #4 starter relay.

I would tend to agree that #3 is a horn relay.
The painless kit should be relativlely easy to install since the wires are marked... My brother and I installed one on a motorhome that uses the same fuse box as a D-100 with the flashers in the box. The most difficult thing was finding out which wire went were since most of the wires in the motorhome were the same color and not tagged.~80% white as I recall.

Day 2: Taking out all the wires.

I had begun labeling all of the wires that were already there, but quickly found that so many loose, unused, and burnt out wires made such a project pointless.

So out came the wire cutters. I made an effort to identify what each component was as I snipped. My father-in-law said he had figured out what that relay was, but I, er, forgot I'll ask him later.

Here's the old wiring (yuck).


Here's 2 pictures of the dash, vacated of their wires



Notice how, when we clipped the wires, we left some exposed; this is because (in theory) the Painless setup is the same colors as the standard Mopar colors. That way, for electrical parts whose plug tabs that aren't well-labeled (which is pretty much all of them), we still have some idea what goes where.


We're mounting the fuse block under the steering wheel and fishing the wire through the firewall hole that used to have the firewall connector. I looked at each bundle and decided if it belonged in the cab or outside; if outside, it was fished through the hole.


The wire coming out of the hood to keep them out of the way.


An artsy shot of the interior wiring.

Looking good so far.

Hacking and destruction is much easier than construction ... so we'll see

Originally Posted by B-300

I would tend to agree that #3 is a horn relay.
The painless kit should be relativlely easy to install since the wires are marked... My brother and I installed one on a motorhome that uses the same fuse box as a D-100 with the flashers in the box. The most difficult thing was finding out which wire went were since most of the wires in the motorhome were the same color and not tagged.~80% white as I recall.

Oh man.... THAT must have been fun.....