Ignition Switch for 74 Ramcharger Problems & Conclusions

So last week, I created this thread in the Q&A Section here:

https://board.moparts.org/ubbthread...g-problem-i-cant-seem-to-figure-out.html

No matter what I did, I was unable to get the new, replacement switches to work. I used 3 Standard Motor Parts Switches, a BWD, and a Wells/Duralast. I have returned ALL of them.

Out of the Different Brands, All but one exhibited the same issue. When wired in, I would get a No-Start condition and Zero Volts to the IGN#2 / Bypass Circuit. One of the Standard Motor Parts switches was completely dead, only let 6V across it, and would get hot to touch fairly quickly. Interestingly enough, 3 of the 5 switches (two Standard and the Wells/Duralas) would crank the truck (still with no voltage in IGN#2 / Bypass during "Start*, ONLY by finding a sweet spot in the switch between "Run" & Start". Here is a video that shows it. I did drop the BS word in the start of the video. https://www.amazon.com/vdp/f516000a882243e0b9ae5a1a6bc1ebc4?ref=dp_vse_rvc_0

I dug around in some boxes of old wiring harness I keep and found an OEM switch, but the wiring harness was cut off a few inches from the switch. I made some temporary jumpers and BAM! Truck cranked right off.

My solution has been to solder on 10 AWG Marine Grade wiring to the OEM switch, then build out a Metri-Pak 6 way connector to have a disconnect under the dash (I Have the crimpers to do this so it makes it easier).

Now before I get trampled about the condition of my wiring harness. The wiring harness in my Ramcharger was pulled out of a 1974 W200 w/ Factory A/C that only had 8,800 miles on it (it had all the same options as my RC except for Cruise Control) and I spread out the harnesses on a table and traced out every single wire verifying them against the Factory Service Manual, AND using my electrical tester to test for continuity. I used a NOS M880 Harness for the Engine Wiring (after lengthening the Coil, Distributor, and Water Temp sensors since it was for a small block).

I'm REALLY hoping that I never have a problem in the future with the OEM Ignition switch because as of right now, I do not think that there is a replacement switch off the shelf that will work for our trucks, and as they age, replacement parts are going to be harder to come by.

Well I was having the same crank no start condition you were describing on my 77 D150. Would crank but would not fire, no spark from coil, would try to fire just a little bit when the switch came back to run. So I checked around and could not find the issue and condemned the switch at the culprit. Put a new Standard switch in. Same issue So I kept digging around and found I had a poor connection at the bulk head connector at pin 18 not letting enough voltage pass through to let the ignition fire while cranking the truck. Made sure I had a good connection and BOOM the truck fired right up. This problem had every once in while would do this but then it would start so I never chased it to hard. Drove the truck to Carlisle this year with no issues on the ignition. Got back parked in the garage and then it never fired again until I chased all this down and fixed it. Might not be your problem but that is what it was on mine.

Before I put the harnesses in the truck, I pulled all the wires out of the bulk head and hit them with a copper wire brush, same with the blade ends on the engine bay side of the harnesses.

A loose connection was not the issue here. I tracked this back to a switch issue. I had my wife probe the contacts on the back of the ignition switches while I cycled it in my hand. I wasn't about to go about installing one until I verified it worked.