Painless Performance 30003 upgrade in my '74

[Yadkin]

I'm staring reassembly of the interior and the first thing is to get the wiring all squared away. I originally intended to stick with the OE 10 fuse panel but found at least three factory in-line fuses buried way up in the dash and I know I'll never be able to get to them this easily again. That, and I found several burned wires and those stupid mechanical splices that cut into the sides of the wire. So I went and bit the bullet on a new panel. The wiring is generally in good shape so saved several hundred dollars and (hopefully) many hours removing the old harness and threading the new one in.

The 30003 is an 18 circuit panel that includes flashers and a horn relay. Retail cost was $260 or so but I found an open box one from Amazon for $200. It took me the better part of a day at my kitchen table inspecting the new panel and mapping it to the old. The only wiring diagram I was able to find was for a '72. To save time running back and forth to the garage I removed the two bolts holding the old panel so I could access the back and then took color photos to reference.

The Fiat flashers (signal and hazard) are wired together in a complex arrangement that works, so I'll likely keep them as is. The car also has a horn relay under the hood so I'll keep that as well. The 3003 doesn't support seat belt warning chimes but I'm removing/ abandoning that system altogether anyway.

Today I cut out the old panel and spliced in extensions, then installed the new panel. There are a couple wiring changes that were not on the '72 diagram and I missed from my photos. There are some white/black wires, maybe the seat belt system, and a small tangle of pink wires, some fused and some not but all in the same circuit, that look like they go to senders on the engine. Also my car has relays for the headlights while the '72 did not.

It looks like I will not be able to eliminate the auxiliary fuses. So to keep things organized I just ordered a 6 unit panel made by Hella for $8. In retrospect I probably should have purchased two 10-fuse units and wired those by hand. It would have been far simpler and cheaper that trying to adapt the 30003.

As a side note, I have not found a ACC wire from the key (lock) switch. There is a mechanical detent there but I have not been able to find voltage from any wire with the key in that position (that isn't one with the key removed). So my new panel only has two power sources. Black (10ga) is battery voltage routed through the starter and is always on. Pink (10ga) is from the lock switch, key on. The only other 10ga wire is from the voltage regular, orange, and is immediately fused down to an 18ga wire in the OE panel, kinda a "what were they thinking" circuit.

[gtmedley]

I did product PR for Painless for a decade, mostly hot rod stuff and V8 fuel injection conversions. They make great products. Their wiring harnesses are a breeze to install.

Also, their retro split woven harness wrap is awesome in Fiat engine bays.

[Yadkin]

Yeah I love that harness wrap. I did my entire TBird wiring with it. I use it to cover small hoses too.

[baltobernie]

Their wiring harnesses are a breeze to install.

They may be a breeze to install in a hot rod or a vintage Camaro, but it takes quite a bit of work to install their Universal kit in a Spider. Their tech support was helpful when I needed them. I offered assistance in developing a harness for the Spider, but they declined. I guess there's not enough cars (or owners willing to spend the money) to justify the expenditure.

I'm sure glad I completed the project though, as I've had zero electrical issues since.

[scrapironchef]

Their tech support was helpful when I needed them. I offered assistance in developing a harness for the Spider, but they declined. I guess there's not enough cars (or owners willing to spend the money) to justify the expenditure.

Yet...

Our cars are getting older and sooner or later this will become a necessary piece of surgery for more and more of us.

[Yadkin]

Well, this has been a tremendous waste of time and money. Poor planning on my part. The 70's European ignition switch is nothing at all like the classic US counterpart of which the Painless panel is designed for. As I was mapping this thing out three weeks ago I was beginning to have my doubts and I should have stopped then. I'll have to make far too many surgical changes to this panel to make it work and have all the circuits operate as Fiat intended.

Last night I removed the Painless panel and ordered a far simpler 16-circuit Hella box, $47 on Amazon to my door. All the connectors for it are shipped loose and I'll be able to mimic the old Fiat panel exactly, and still have room for the small handful of auxiliary fuses that the factory cobbed onto the earlier designed panel.

[spider2081]

This is the fuse panel I like to replace the original Fiat and VW fuse panels with. Copy and past the link.

https://www.ebay.com/i/282865594016?chn=ps

It has 13 fuses so there is room for extra circuits. Also it is shorter in length then the original panel. so it fits in the original location after fabricating a couple Z shaped brackets. The original fuse panels have fuse inputs 3&4 5&6 7&8 9&10 jumped together, the Lada panel does not. It has two input and 2 output terminals for each fuse so the original fuse panel is easily replicated.

[Yadkin]

That's a good choice since it uses the same wire terminals at the OE. Unfortunately I already cut thos to replace with the fork terminals for the Painless.

Here's the Hella that I ordered. I like it because several terminals can be kept together as a bus, eliminating tagging wires together.

[spider2081]

it uses the same wire terminals at the OE.

This is true almost a plug and play. I do replace the fuses with Buss or little fuse brand as they are better quality.

I like it because several terminals can be kept together as a bus, eliminating tagging wires together.

Thats a good point.

[Yadkin]

Here is my wiring map for the new box.



I decided to change the circuit function a bit from the factory. "Relay A" will take power from the #1 source (constant battery 12 volts) and controlled by the ignition switch pink wire (run). I'll use the feed from Relay A to power three fuses, and these will serve the following functions: heater, windshield wiper, windshield washer, back-up lights, brake lights, and radio. What that will do is allow key-off to power down all those circuits and reduce the electrical load on the switch. Meanwhile the pink wire will still control the more critical fuel pump circuit without relying on a relay, only a fuse. The car will still run if Relay A fails.

For the #1 source wire, I'll need to check the size. The total fuse load on it is 65 amps (5 fuses), and they could all be running at the same time. I'll probably run a #8 from the factory terminal on the starter to a splice, then feed the #1 - #3 fuse buss with a 14 gauge wire and feed Relay A with a 12 gauge wire.

[Yadkin]

I don't see a good way to crimp large wire sizes onto the small connectors that the Hella box uses, so I took another look at the Painless box and developed a map for it.



The Fiat harness uses four fuses for the headlights. These are fed by two wires from the headlight switch, hi and lo, and then left and right have their own fuses. The Painless panel has two "aways on" busses jumped together to power 9 fuses plus a relay. I'm able to isolate two fuses together off of one buss, hazard and horn, to use for the low beam fuses. The panel also has an accessory buss powering three fuses that I can use for the high beam circuit. I'm using the third to protect the indicator lamp circuit independently.

For the aftermarket radio that has an "always on" memory circuit, I'm using that to power the radio itself, so it won't turn off with the ignition key.

[Yadkin]

I added in the terminal designations and describe the minor wiring modifications needed.

[Yadkin]

Well, I found a wiring diagram for my '74. Compared to the generic one from the Haynes Manual that I had been using to plan this, the fuse layout is completely different. So back to square one for my panel wiring layout.

It also solves the mystery of the round socket device with 12 wires going into it, and a host of relays buried in odd locations. The device is an interlock, connects the seat belt warnings mainly, but also a sub-relay that controlled the main starter relay. Other relays turned off or did something to the distributor and fuel pump depending on a water temperature and oil pressure limit switches. I'm guessing that the system reduced power or shut it down to save the engine if you happened to ignore the temperature gauge or the oil pressure warning light. All of that crap has the potential to reduce the cars dependability, so it will all be removed. No wonder these ars had a reputation for bad electrics.