My 1952 Plymouth Cambridge needs an electrical upgrade. I’m tired of the electrical gremlins, random horn honking, unreliable headlights, dim tail lights, etc. I want to go from a 6 volt to a 12 volt system with a new harness. Questions: 1. Should I jerk the old harness out and THEN route the new? 2. Should I piggyback the new and then pull the old? 3. EZ or Painless? I looked at Francis, but that’s a bit rich for my budget. 4. I want to add an electric fuel pump to help out my mechanical. Should I just get rid of the mechanical? Whew! So many questions, eh?? Any help you more seasoned guys could throw in my direction would be great! And yes...I want to go to a new 12 volt alternator. Thanks a ton in advance!
Tell you what I did with my Buick. The Wrapping was coming off the harness, so finished the job. Labeled each wire. Removed and layed out on work bench. Cut new wire to match. Attached connectors. Installed. I used the original fuse panel. Would use a modern one if I did another. Good idea to have a wiring diagram in hand. Alternator for sure. I recorded in a note book each wire by color and size and where each end is connected. I enjoyed the experience. Ben
I used a Kwik Wire harness in my Buick. All the wires are labeled every foot or so, and everything worked first time. I believe it even had a wire for the fuel pump, which I didn't use, but I could be wrong on that as it's been a few years. Regardless of what harness you use, take some pictures of the wire routing and then pull the old harness. You will have enough wires to contend with with just the new harness. No sense having another harness in the to confuse things.
Take photos of how the OEM harness is routed and installed in the car. Then disconnect each OEM wire and carefully label what that wire connected to. Then remove the old labeled harness and lay it out on garage floor. Lay the new harness next to it so the wiring corresponds and then label that also. The idea is to have the new harness match the OEM harness. Then install the dash wiring harness. Then the engine and headlights harness. Then install the harness that runs to the rear of the car. It helps if you have the OEM wiring diagram/schematic. That's how I did it. Other approaches will vary.
I'm redoing my '38 right now. Being too cheap for a harness I am making it starting with what's needed to make it run and going from there. As I'm also contending with a conversion to negative ground and retaining 6v gauges.
Definitely remove the mechanical pump. When the mechanical pump diaphragm starts to leak, the crankcase fills with gas - diluted oil is not a good thing.
Check with Rebel Wire before you invest in a new harness; they're an Alliance vendor and some great people, they have an excellent product, reasonable prices- and the best tech support I've found in the industry. As to the routing and such, I would suggest leaving the old one in place until you are ready to install the new harness. That will allow you to see where to route wires and provide you with a way to pull the new one thru tight spots using the old one. If you want to move to an electric fuel pump, I would completely bypass the old one but leave the old one in place; you won't have to build a block-off plate and, to a casual glance, will look original if that is important to you. 6v to 12v is easy enough, there is a ton of info available here on HAMB and Google. I used these folks to do my 6v positive ground to 12v negative ground conversion when my '51 Ford still had the flattie 6 cylinder in it. Good luck on your project and don't be shy about asking questions here; the people here on the HAMB were great and helped me through my conversion, answering even my really dumb questions without making me feel foolish (which I really appreciated, I had big trouble wrapping my head around 6v positive ground, it still makes my head hurt).
The instruction book that Kwik Wire has beats anything else out there. It was quite easy to follow and I had little trouble. I'd use them again.
X2 on Kwik Wire. I did my 49 Buick with a one of their harnesses, and found the instructions great. Hooked it all up and everything worked as it should. I think that says it all.
Their instructions, I could see them up front before I committed to buy their product. I have the booklet in a binder with all my notes I took during the installation.
I like American Autowire, and have used their add on pigtails as well as rewired a few cars completely with the universal "Builder" and "Highway" series since they were not stock applications. The painless stuff I've used has been ok, (it might have been the specific kit I didn't like as it was pre-terminal'd , but I'd like to try out the Rebel Wiring stuff sometime. They are spendy, but Rhode Island wiring will make you a direct swap 1952 Plymouth stock harness harness, correct wiring, loom, etc. but I would expect it to run close to a grand, but would take some of the guess work out of using a universal harness. I've never used one, too rich for my blood, but being a semi local company, have seen their stuff in use and its nice.
Hey, has anyone ben able to rebuild their original switches? I want to do the conversion and I have every OG part and would hate to have one new switch that is new... for headlights or whatever.
19Fordy Check this out... I wonder how well these work... https://www.ebay.com/itm/Hot-Rod-GM...375609?hash=item23bad4fbb9:g:GfIAAOSwgRpbZJLd
I don't have much experience wiring rigs. But I wonder how hard it would be to adapt these switches to the 49' 6-12v conversion kit in the link below. https://www.vintageautogarage.com/1949-1953-Ford-Mercury-Car-Truck-V8-12-Volt-Kit-p/f4953612k.htm
Found this video In the process of converting a 1954 Chevy Belair this week Good info! Sent from my iPhone using The H.A.M.B. mobile app
My city job sent us home, for 2 weeks, so it gave me a golden opportunity, to focus on that 12 volt conversion. 95% done, as of this afternoon. Most everything seems to be working correctly. Only 2 items, not addressed, were heater blower motor and radio. (both did not work prior anyways, so not concerned) Did buy the Speedway HD voltage reducer, for blower motor, but it was disconnected, so unsure if it even works. in short, wound up swapping in a GM 12v battery, alternator(with special diode pigtail), flasher, coil and condenser, as well as, all the lightbulbs. Also added 1 Runtz voltage reducer to fuel gauge. Hard wired yellow wire off alternator, to B+ at coil and spliced 2 HD leads that were connected to voltage regulator, to provide B+ to alternator. Fires right up cold and hot now. Big difference. Old stale gas keeping it from running 100%, but not worried. can deal with that later. Stoked that all lights work correctly and even the dome light turns on when door opens. It's the little things in life, that mean the most. Ha Between the HAMB, aforementioned YouTube video, Jeremy at Rebel Wiring and Randy Rundle's "the official 12 volt conversion guide"...I must say, the job went smooth.(8 hours???) Eckler's 235 alternator bracket, had to be modified. Mounting holes/slots, were too small. Rotary file made quick work of fixing this. She's charging at 14 volts and shutting off, just like it's supposed to. Most importantly, the hot start problem is gone!! A little tidying up tomorrow, of loose ends and fresh gas should put the lid on this. As of Thursday, Orange County will be on lock-down. Ugh Glad I've plenty to keep me busy JT P.S. elarges, did not mean to hi-jack your thread, but if anyone has questions pertaining to Stovebolt Chevy, don't hesitate to ask. Runtz blue voltage reducer bolted to back of gas gauge Leaving seat out after carpet install made it so much easier to lay under dash
Here's how I've done probably 20 cars and dozens of Harleys....treat the electrical system as basically 3 separate systems; Charging circuit Starting Circuit Lighting Circuit mount an ignition switch and a fuse block and whatever other switches you will use (headlights, wipers etc.) leaving them only hand tight so you can pull/reinstall as needed. (tighten down when all done) do only one circuit at a time. I usually do charging then starting then lighting in that order, but it really doesn't matter the order. Get you a schematic if you need, after awhile you wont need one, make 3 copies....highlight only the one circuit your working on till its done, then continue on with a new circuit and schematic, with whatever circuit you are doing next and so on. by doing the charging first, one of the first thing you run is a hot wire to your ignition switch (after the amp meter if using) allowing you to check as you go along by using the ignition switch as an off/on switch. check your work often so if you have an issue you only have to backtrack to your last check. By breaking it down in 3 separate jobs, you will be less apt to get really confused...If you come to an issue you can't figure out, 90% can be figured out on the schematic...if not Google is your friend...such as, can't figure out the alternator wiring, just Google only that single issue. Pay attention to correct wire size recommendations.... All this being said, I am NOT an electrician, but have done this so many times I can do it blindfolded and very seldom an issue has arisen and I actually enjoy this part of the hobby...WAY more than body work. Nothing like a neatly wired, well secured wiring system...I get compliments all the time on my cars and bikes... on a side note...by uninsulated amp ends and use red and black shrink tubing at all joints...red on anything hot and black on everything else. don't worry about soldering the amp ends on...I used to do this until I worked a year on the construction of Diablo Canyon Nuclear Facility and noticed those electricians never soldered any joints or connections, just make good crimps.
Rebuilding switches? If they are like many of the older switches they have a metal box with a "fiber" back with the terminals on that. That's the way Studebakers did it, at least with the Studebaker Hawks. I have disassembled a few of those and had some success, sometimes the switch is toast but most of the time they are grungy and just need a good cleaning as well as burnishing up the contact points. You will have to bend the metal tabs up to release the fiber board with the contact points, there can be little springs to jump out so watch them so they don't escape Here are pictures of the turn signal switch (just the part with the contact points) and a picture of the heater/defroster switch disassembled. The Hawk switches are toggle style, I suspect yours will be a little different.
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