Relay confusion3 VS 5 wires

[Tornadosailing]

I'm curious. How did you determine you needed a new relay?

[Hoghead]

Originally Posted by Tornadosailing

Yes. The Delco horn relay should work. There's a version with push on spade terminals.

The next task would be to match up the function of the terminals so it will actually work. A test light or meter will be needed. One wire will come from the battery, probably with a fuse. One will go to the start switch and will be ground when startling. The last one will go to the starter.

Fat chance of finding a Delco horn relay in the Philippines

I do have a Bosch relay but stumpted on how to wire using only 3 wire. Is this correct?
Start switch (key) to 86
Starter to 87
Battery to 30

[Hoghead]

Originally Posted by Tornadosailing

I'm curious. How did you determine you needed a new relay?

It works, but the case is very corroded and I just do not trust it anymore and would feel a lot better with a nice new relay.
There are enough things that can and do go wrong without inviting trouble at the least opportune time

[flee27]

"I do have a Bosch relay but stumpted on how to wire using only 3 wire. Is this correct?
Start switch (key) to 86
Starter to 87
Battery to 30 "

Above is correct. In addition you would also need to ground terminal 85.

[Tornadosailing]

Originally Posted by Hoghead

Fat chance of finding a Delco horn relay in the Philippines

I do have a Bosch relay but stumpted on how to wire using only 3 wire. Is this correct?
Start switch (key) to 86
Starter to 87
Battery to 30

Since the original relay no doubt uses the start switch to ground the relay coil (use a meter to make sure), you need to supply power to the coil. Simply make a jumper to go from 30 (battery) to 85. The start switch should ground 86, completing the circuit.

I understand your concern about the rusty case, but the case literally just contains the important parts. You could clean and paint it.

[Tornadosailing]

Originally Posted by flee27

Above is correct. In addition you would also need to ground terminal 85.

3 wire relays like his original normally have an internal jumper from battery to the relay coil. To energize the coil you have to ground the other side. These relays were common for horns where you would run a single wire to the horn button, which would ground it to the steering column when pressed.

[TreblePlink]

If it is working, it might be best to wait until you can get an exact replacement - particularly if you're not sure about rewiring ...

[Hoghead]

Originally Posted by Tornadosailing

Since the original relay no doubt uses the start switch to ground the relay coil (use a meter to make sure), you need to supply power to the coil. Simply make a jumper to go from 30 (battery) to 85. The start switch should ground 86, completing the circuit.

I understand your concern about the rusty case, but the case literally just contains the important parts. You could clean and paint it.

I can only wonder what the important parts look like inside that case after 40 years.....

I am going to wire the Bosh relay this way, and will advise if it does not work and I smoke something!!!

Thanks to all for the help