Onan Start Relay - One Size Fits All

[lokay5]

Yes, a Ford relay WILL work on an Onan... if that Ford relay is a Ford Part Number SW220 or an AMC Part Number 3227812 or a Chrysler Part Number CH 2336 or a Delco Part Number 1114206

The SW220 has an isolated coil, meaning that the relay's pull-in coil is not internally connected, so it can be used on any Onan, regardless of how the OEM relay is internally wired, because the coil in the SW220 terminates at the relay's two smaller terminals, and is not internally connected to either of the larger switched terminals.

Connect one small coil terminal to the relay's large terminal that's connected to battery +, and the relay will close when the other small coil terminal is grounded to start.

Ground one of the small coil terminals with a jumper under a mounting bracket bolt and the relay will close when the opposite small coil terminal is connected to battery + to start.

Good work. How did you come up with those numbers that's great news ?

[YellowLister]

That's cool. I found them for 13.99 to 28 bucks. Onan solenoids are about 25 to 35 shipped. Good info if your in a pinch and don't have a spare

[Jack Hottel]

I beg to differ . Onan PN 307-0845 connot be replaced with a 4 terminal device. The I terminal is needed as an isolated source of 12V. Here is a link.
Jack Hottel
http://www.smokstak.com/forum/showth...d+for+307-0845

[Lloyd H]

Jeep used a ford type solenoid that had an isolated coil plus an "I" terminal as well. 5 terminals total

[PnishrPW]

Napa ST-83 is also a 5 terminal unit, ~$18 locally. This is from a Jeep/AMC application.

[lokay5]

Originally Posted by Jack Hottel

I beg to differ . Onan PN 307-0845 connot be replaced with a 4 terminal device. The I terminal is needed as an isolated source of 12V. Here is a link.
Jack Hottel
http://www.smokstak.com/forum/showth...d+for+307-0845

From the link-


"From what I have read (and verified by the pictures), the solenoid has an insulated case. The coil is always hooked to 12V+ though the large battery input terminal on the left. It is activated by the small S terminal when 12V- is applied. The I terminal becomes 12V+ during crank through the copper foil shown in the picture."

The large terminal that's connected to the start winding goes positive on crank. Why have a separate terminal?

[PnishrPW]

"I" terminal is generally used for sisson choke equipped models.

[lokay5]

Originally Posted by Kpack

Good work. How did you come up with those numbers that's great news ?

Thanks!
I cheated. I have a Cole-Hersee catalog that shows the internal wiring of each solenoid. The12V relay with an isolated coil is Cole-Hersee number 24023
I crossed 24023 on line and got all the interchanges. There are more, too. LOTS more.
Just type in Ford SW220 or Cole-Hersee 24023.

Originally Posted by PnishrPW

"I" terminal is generally used for sisson choke equipped models.

And it only receives power when cranking? And if so, why isn't it just connected to the start winding terminal?

Originally Posted by Lloyd H

Jeep used a ford type solenoid that had an isolated coil plus an "I" terminal as well. 5 terminals total

If I remember correctly, the "I" was "Ignition". It bypassed the ballast resistor and supplied 12V to the coil for a hotter spark when cranking.

[PnishrPW]

Backfeed would keep choke on.