1952 Chrysler 6V starter relay

[nickg112]

I have a 1952 Chrysler Town and Country that I am having problems starting. The starter does not crank. The starter solenoid mounted on the starter is not getting power from the 6V starter relay. This relay is mounted on the driver side inner fender. The car has positive ground. 

 

I want to bench test starter relay to be certain this relay is not my issue. These starter relays are not available anymore. Part number is HRW 4001a. It has three small terminals and one large terminal.

 

I have attached a photo. I want to make sure mine is working correctly and would like to bench test it.

 

It has three small terminals as shown and these three terminals are wired  as follows:

• Middle terminal has a wire that connects to the starter solenoid. I do not see any voltage going to the starter solenoid from this terminal when I turn the ignition key.
• The terminal to the right of the middle terminal has a wire that goes to the ignition. When I turn the ignition key, I see 6 volts going to this terminal on the relay.
• The terminal to the left of the middle terminal has a wire that goes to the voltage regulator. I do not see any voltage at this terminal

The one large terminal has a few larger cables with one coming from the battery,  and one goes to the starter. The large terminal on the starter is getting power.

 

I have inspected the inside of the starter relay and everything looks good. Nothing looks burnt and I do not see any burnt wires.

 

Any suggestions or advice would be helpful

[tom1954]

I can't help you on the testing of your system but I can tell you the relays show up on ebay from time to time. I recently bought a spare one for my 54 on ebay for $200.00. I have seen them go for as high as 400.00. I have also seen a few folks that used a Ford style relay / solenoid in its place. Good luck.

[c49er]

Open it up and clean the contacts...simple...you won't find one of those easily. Or cheaply.

[nickg112]

8 hours ago, tom1954 said:

 

I actually found one of these on ebay for a good price. It worked for a day but now I have an issue again. Starter does not crank. I know my starter and solenoid are both good. Not sure if it is the starter relay and that is why I wanted to test it. I like the idea of using a Ford relay but that has 2 small posts and 2 large posts. Not sure how I would wire that.

 

When I look at the 52 Chrysler schematics, I do not see a ground on this starter relay. Does anyone know if the body should be grounded?

[Bloo]

Ok, you have 6v from the battery on the big terminal, and a center terminal feeding 6v down to the starter solenoid, right? These are the relay contacts. (They are also the two big posts on a Ford relay, but never mind that for now.)

 

You have 6v from the key "crank" position feeding one outside terminal. Good. That is one end of the relay coil. The other end of the relay coil is the only mystery. It would need to be grounded to crank.

 

A few years later, in the 12v days, Chrysler typically floated that ground and ran it through a neutral safety switch. That MIGHT be your last terminal. You said it goes to the voltage regulator. Which terminal? It MIGHT be a ground contact that keeps you from engaging the starter if the car is running. Also, does the car have any sort of clutch or neutral safety switch?

 

I have no access to the wiring diagram. I gather you do. Follow that wire. It probably leads to the answer.

 

 

Edited October 7, 2019 by Bloo (see edit history)

[AlanT]

In those days, one wire of the relay would connect to the generator (as relay ground) to ensure that the starter could not be engaged one the generator is turning (producing power, the engine is running). So the generator armature is the ground for the relay, allowing the relay to be activated. When the generator is producing voltage, it is no longer ground. Both sides of the circuit go to battery voltage when the gen is turning (at speed), thus no current flows through the relay. In later years (1957, 1958) they used a vacuum switch to disable the starter relay so it wouldn't engage while the engine was running, instead of grounding the circuit through the gen armature.

[nickg112]

12 hours ago, Bloo said:

You are correct. I have the big terminal and the center terminal feeding down to the starter solenoid.
The terminal to the left of the middle terminal has a wire that goes to the voltage regulator (Arm). This is what my schematic shows also. I think my issue may be this terminal. Since power is going into the starter relay but the wire leading to the solenoid is not sending power, my guess is I do not have a ground.

I have checked and cleaned ground wires and everything seems to be wired correctly. I am posting a schematic of the area

 

[Bloo]

7 hours ago, AlanT said:

So the generator armature is the ground for the relay, allowing the relay to be activated. When the generator is producing voltage, it is no longer ground.

 

I wonder if the generator brushes are just shot?

 

4 hours ago, nickg112 said:

my guess is I do not have a ground.

 

I think you could find that wire that goes to the voltage regulator and disconnect it at the starter relay. Tape it up or something because it will be hot if the car starts. Then, ground the terminal on the starter relay that you removed the wire from.

 

If that makes it work, you may need to go looking for trouble inside the generator, or a broken wire somewhere in the starter relay >> regulator >>> generator area.

 

If it doesn't make any difference, then its time to take a close look at the relay again, and make sure the other connections all still test good.

 

 

[c49er]

The contact points are almost always the issue with these 1951-54 Mopar 6 volt cars. They need to be carefully... lightly filed clean.

But here is the way I bench test them....

1) Connect the Battery charger leads -(NEG) to the BIG relay Stud...connect the + (POS) to the relay base for a ground

2) I ground one of the outer top studs (top left) to the relay base with a jumper wire.............actually connects to the Regulator or GEN "ARM" terminal on the car for the relay coil Grd.

3) I connect a jumper lead  to the BIG bat cable 6V feed stud and tap touch the other end of the jumper wire to the right stud which closes the relay points making the clicking . Doing this closes the relay points sending 6 volts to the starter solenoid via the center relay stud terminal.

4) The center of the three studs is the 6V feed wire to the starter solenoid.

.I connect my volt meter to that stud and the relay case ground to check that 6 volts is supplied to this center stud as the relay contacts close.."click"

 

 

Edited October 8, 2019 by c49er (see edit history)

[nickg112]

A lot of great information. I will be working on the car this weekend. I will report back. Thank you so much

[nickg112]

Turns out that at some point I reversed the wires on the starter relay. These were the ignition wire and the voltage regulator. if you look at the attached schematic, I had them wired exactly as indicated. I discovered that these wires were wrong when I removed the relay. I sanded the case and saw words IGN and Arm and noticed that was not as indicated on schematic. I reversed the wires and it works fine now. The car starts.

If you notice the schematic does not have ARM and IGN marked. I just had mine on the side indicated. It's all good now. Thanks for the help.

[Bloo]

Glad you got it sorted!