4104 General Light Relay

[pennuja]

I was doing some wiring to the bus tonight and I was planning on repurposing what I thought was the general lighting relay to use it to remotely power some things on and off from the front while driving. I can connect 12V and ground to either of the silver relay's in the picture but neither seem to do anything (I am using the two smaller posts Left as ground and Right as 12V). When I got the bus these were disconnected in the front electrical compartment because the lights on the output of them were shorted. I guess it is possible that they are both bad, if that is the case I will just replace them.

These are relay's aren't they?

Thanks,
Jim

[Gordie Allen]

Generally, I think most people refer to these as solenoids. They are relays generally designed for loads over 40 amps. Modern four post spade relays are only about 1.25" cubes that connect with spade connectors. I'd recommend replacing all our wiring except for the heavy power cables. The original wiring is insulated with cotton wrap and is not safe or reliable. It;s not as hard as it sounds. You can tear out those huge boards and all the spaghetti in both the front and rear. My rear electrical compartment has three relays and a fuse block and that's it. The engine only requires three relays - starter, reverse, and "engine on". In the end you'll have a completely reliable system that's safe.

[gus]

I was doing some wiring to the bus tonight and I was planning on repurposing what I thought was the general lighting relay to use it to remotely power some things on and off from the front while driving. I can connect 12V and ground to either of the silver relay's in the picture but neither seem to do anything (I am using the two smaller posts Left as ground and Right as 12V). When I got the bus these were disconnected in the front electrical compartment because the lights on the output of them were shorted. I guess it is possible that they are both bad, if that is the case I will just replace them.

These are relay's aren't they?

Thanks,
Jim

It is unusual for the low amp coil side of these relays to fail, usually the large terminal side fails because of arcing inside. I never found a bad one on my 4104.

If you apply 12v to one small terminal and ground the other there should be a definite loud click, makes no difference which terminals you use. Maybe your grounds are not good.

If you replace these with like ones remember they come both in instant and constant service types so match them to your planned uses.

[pennuja]

Thanks guys.

Gus when I connect power and ground I get a slight spark and no clunk. I figured that they would clunk, I ordered a different relay but I am going to remove them and test again. Maybe my ground is not real good.

[digesterman]

If I am seeing two small terminals then just hit those with neg and pos power, Napa has constant duty ones for around 40$, heavy duty ones that is