Ok guys, I'm still putzing with the overdrive in my 49 ford. It has an 8ba flathead with 3 speed and od and has been fully 12v neg converted. I parked the car the night before my father's celebration of life and the od worked fine. The next morning I get the car out to take it to the celebration and now the overdrive don't work. No click from the relay, nothing. Pulled the solenoid, cleaned the contacts, bench tested and it works fine. Pulled the fuse on the relay and it's not blown. While fuse was out, I turned the key on and checked the ignition switch side of the fuse and I have power going to the relay. However, when I put the fuse in, shouldn't the relay click when I turn on the key? I'm not real good electronic wise and I'm looking in my green book for clues as well.
That relay only operates when you floor the gas to downshift out of OD or if you're going fast enough for the governor contacts to close. Try grounding the wire from the governor, if the relay doesn't operate the kickdown switch is bad or the relay has failed. If the relay works, the problem is the governor. Ground the wire on the relay that goes the kickdown switch. If it does work, then the switch is bad. The kickdown switch has one set of NC contacts (that power the relay) and another NO set that momentarily grounds the ignition when you tromp the gas. The governor can be dis***embled and the contacts cleaned most times.
Relay shouldn't click until I gets it ground from the governor. Not 100% on the '49 but generic o/d wiring is 3 powers (2 in and 1 out) and 1 ground. Check the other side of the fuse holder (power in and out), IGN should have power with the switch on, BATT should have power, un hook the TH. SW. wire, run a ground wire to the TH. SW. post and you should hear a click and have power at the SOL. post. If you don't have power at the SOL. post after above then suspect relay. If it works the check governor circuit (including the kickdown switch).
Print your own copy of the manual halfsack shows. Cost more than 50 cents in ink and paper now. https://www.oldwillysforum.com/forum/TechData/BWOverdriveManual.pdf
Ok, so I went and bought a 12v 30a relay today, as well as a lighted toggle switch. Is there a diagram out there that I can use to wire this up ?
Post a pic of the relay, they're different ones. The good one will have the schematic printed on the side. Also post a pic form the factory repair manual. Your pic of the relay looks like it has 1 power in from the IGN, the ground from the governor goes through the kick down switch to the TH SW tab on the relay, closes the contacts and sends power out of the SOL tab.
Okay, it looks like you are going to start changing parts without thorough troubleshooting. The first thing I would do is check all the wiring for the OD. You might just have a connetor that came apart. You will have to go under the car to see the governor, OD solenoid and kickdown switch wiring. The relay supplies power to the OD solenoid when the transmission governor provides a ground (around 28 mph). With the ignition on, the relay should click if you use a jumper wire to ground the TH SW terminal. If it clicks and you now have power at the SOL terminal, there is nothing wrong with the relay or the wiring to it. I would next get under the car and disconnect the governor wire. If you ground this wire and the relay clicks, the kickdown switch and the wiring to the governor is okay. If it doesn't there is an open circuit somewhere between the governor wire, kickdown switch and the relay. If all that checks okay, I would disconnect the black wire at the OD solenoid. With the jumper wire to ground on the TH SW terminal you should have power to the black wire on the solenoid. If you don't, there is an open wire between the relay and the solenoid. If all that checks good, I'd remove the jumper, make sure all the wiring is connected, put the rear end up on jack stands, put the car in gear and get the speed up to about 30 mph. The relay should turn on sending power to the OD solenoid. If it does, the governor is good and the kickdown switch is good. If you get this far and everything to this point checks good, your problem is either the OD solenoid, or there is something wrong internally.
I don't believe there is an internal issue as the overdrive was working beautifully the night before. With the overdrive handle pushed in, it freewheel like it should, but at 28 ish mph, no click from the relay. I could hear the relay click before. With the od knob pulled out, the 3 speed works like it should in direct drive. All of the od wiring is new from Dennis carpenter, the kickdown switch is new, I don't use it, but it's new. I did check the relay and I am getting power at the ign terminal as well as the other side of the fuse. However I haven't done the jumper wire to the THSW terminal yet. I did pull the solenoid out which I believe to be the original solenoid to the car, as is the relay. I pulled the solenoid apart, cleaned the contacts, re***embled it, and tested it and it works as it should.im trying to learn what I can through the green book and my borg warner overdrive manual as well as help from on here. I will look into everything else you mentioned too. It has to be something so simple.
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