Glow plug relay question

[Rassmuss]

Got a new GP relay that has "BAT" scribed into the relay at one of the terminals. Newbie question, but is that where the 12V from the resistors should go? The truck did not previously have a relay so I'm starting from nothing.

Part of why I'm asking is if I connect it this way it's not oriented the way I see them in pictures Google etc. Does the orientation even matter as long as the wiring is correct?

I'm new to the CUCV scene so take it easy on me. I've been looking over the TMs and plan to post up pictures of the trucks soon. They are a '86 M1031 and a '85 M1009.

Sent from my SM-G973U using Tapatalk

 

[Keith_J]

Yes, it matters on some solenoids. Some may have a diode in parallel to the coil to snub back voltage generated when the solenoid disengages. The magnet field collapsing causes a sharp reverse current which arcs switch contacts and lets magic smoke out of transistors.

If labeled BAT, it connects to the black-pink wire. The blue wire on the other small terminal goes to the controller where it is connected to ground to activate glow plugs. Hook it up incorrect and you will pop a fuse or worse. Test polarity before connecting, +12V goes to the BAT terminal, a test light is enough.

The large terminals don't matter on polarity as they are just contacts

 

[Keith_J]

This polarity warning applies to all solenoids, marked or not. How do you know if there is a protection diode? Markings are there easy clue. But some aren't marked, testing with a multimeter is the only way to be sure.

The diode symbol should be in the circuit diagram but it isn't in the TM. Off a 12 volt system, the back kick can be over 100 volts and several amperes. It can draw a fat spark. The diode acts as a short circuit to this reverse current, dissipating the energy in the resistance of the coil.

 

[Rassmuss]

I forgot to mention the relay is from Hillbilly Wizard. Supposed to be the correct relay for the CUCV

Sent from my SM-G973U using Tapatalk

 

[Keith_J]

Small terminal closest to the labeled Bat input terminal should be connected to the black-pink wire. Other small terminal goes to the blue wire. Naturally, large terminal labeled Bat will connect to the resistor bank other large terminal goes to orange glow plug wires and the thinner orange voltage sense wire.

 

[Rassmuss]

Keith_J, Thank you for the replies. In most images/diagrams I've seen the greenish wire is adjacent to the 12V terminal and the pink/black is next to the glow plug terminal. I just don't want to hook it up incorrectly and burn up anything...including the new control card I purchased.

Sent from my SM-G973U using Tapatalk

 

[Keith_J]

Do you have a multimeter? Measure the coil resistance in both directions, use the higher resistance for polarity. If you get 400 ohms with the red lead on terminal 1, that will be the terminal the black pink wire goes to.

I have the same Trombetta solenoid in mine, I can measure if this is significant.