Painless Harness - Ignition Switch issues

[Dlesage23]

I’ve gone through 4 ignition switches in a year on my Bronco. I have a painless wiring harness and seem to be burning through ignition switches. Everything runs fine for a while and then without warning, I have power when the key turned to On, but when I take the key to Start, I lose all power to accessories and everything. The engine doesn’t even try to crank.
I replace the ignition switch and the issue is gone for a few months. I am at a loss as to what could be causing this. A friend recommended this Hot Shot Relay, but I’m not sure this would address the problem I’m seeing.
https://www.summitracing.com/parts/...cuRNGE7Bqt5WpLLCTZg-e0E4ZhmCReysaAiWsEALw_wcB

 

[DirtDonk]

While the modern iterations of electro-mechanical parts are generally considered crap compared to what we had thirty years ago, yours seems pretty extreme.
What kind of accessories are you running through the system? Any high load items running off of switched-power?
What about the starter? Are you running a modern PMGR starter with the solenoid attached directly from the switch? A few members have tried that over the rears (instead of retaining the fender mounted relay/solenoid) and found their switches failing early too.

Regarding the accessories not working, that's how the switches are designed. So when your accessories are working, that's showing the switches are defective when new!
At least that's how they're supposed to work normally. The ACC feed wire on the center stud of the ignition switch loses power when the key is turned to START.

When the engine does not try to crank, the switch is obviously failing, or the wire is. But since a new Painless wire setup is less likely to be at fault than the switch, I'd still lean toward the switch being bad. Strange that the START circuit is the one that fails though. Hence my question about the type of starter.

Are you utilizing the Brown wire on the "I" post of the starter relay? When you say it's not cranking, you mean that the starter is not cranking at all, correct?

Paul

 

[ransil]

Maybe too much load on the switch, add relays
crappy switches find an NOS bronco switch

 

[Dlesage23]

Thanks for the replies!
The only accessories I am running is the RetroSound radio, so nothing high-load.
I am running a PMGR starter, but my switch goes to the fender mounted solenoid.
That makes sense about losing the power to the accessories when I go to crank, I guess I was looking for as many symptoms as I could find.
I am not utilizing the brown wire on the I post. I’ve gone back over my painless book a few times trying to look for a smoking gun, and one thing I had to do was run a 4ga jumper from the battery side post on the solenoid to the starter because my starter was staying engaged for several seconds after ignition. Would there be any way that I’m drawing too much current through the switch on startup? Like cold starts where I have to hold the key a little longer?
Yes, when I try and start it is not cranking at all.
Any lead on a NOS switch?

 

[DirtDonk]

The larger wire for the starter would not create issues for the ignition switch.
The jumper aspect is the way it's supposed to be wired ultimately. Running both the starter cable and the solenoid's smaller wire on the starter side of the relay can work, but as it turns out sometimes people have that run-on issue you spoke of.

Yes, having to crank the starter for longer periods does put a slight extra load on the switch, but I would not expect it to be too much for a decent switch.

If you're not running an EFI setup with computer controlled ignition, I would reinstall the Brown wire circuit to give a bit of additional current capacity to the ignition during starter cranking. Just seems like a good idea.
What's your setup? Carb and points? Carb and electronic ignition? EFI?

Paul

 

[DirtDonk]

Before you go to the hassle of adding another circuit (the Brown "I" wire) you could run a temporary jumper wire from the battery to the coil positive (VERY temporary!) to see if it starts any quicker when cold or hot.
If it does, then that's a good sign you could use the extra boost of the I wire circuit. If no change, then probably no need to go to the trouble.

As you probably know or have heard, don't leave the jumper wire connected for very long any time the engine is not running. It overheats the coil just like leaving the ignition in the ON position and forgetting it.

Paul

 

[Dlesage23]

I’m running a carb and electronic ignition, the painless manual said I didn’t need the brown wire if I’m not using a ballast resistor. Think I should still install it, or at least try the jumper across the starter?
That wouldn’t be the cause of the ignition failing though, right?

 

[Dlesage23]

The bronco is not at my house right now, I’ll hopefully get to work on this tomorrow.

 

[DirtDonk]

I see. No, no problem without the Brown wire then. Adding one would still has the potential to add more current to a hungry ignition, but in 90% of the circumstances and setups it would not help. And certainly not for adding life to your ignition switches.

Got pics of your setup under the hood? Especially the starter relay/solenoid and battery area?

Back to your original post, your friend had the right idea with the HotShot relay, but it would not help in your case since you literally already have one in the form of your Ford starter relay on the fender.
The HotShot was designed to help GM vehicles where the ignition switch was wired directly to the starter solenoid on the back of the starter. When they get hot, especially after headers are installed, the cranking can be very weak. Some people started adding Ford starter relays on their Chevy's back in the late seventies or early eighties if I remember, and it helped get rid of the problem.

You don't have a slow cranking issue (just a long cranking issue, which is not all that long from the sound of it) and your starter is already handled through a relay, so your ignition switch does not see the full load.

But I'd still be curious to see how yours is wired.

paul