2G Vacuum pump and clutch cut

[v8s_are_slow]

I have a relay for my vacuum pump for my auto and relay for clutch cut both wired to the brake switch. But if I try and use them both at the same time, it pops a fuse. Can anyone tell me if this wiring would be correct? Both are connected to the brake switch. I'm terrible at wiring, just going off these diagrams I found on the forums. Thanks!

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[steve]

I'm not sure what your notes are on the diagrams telling but let me talk generally. It would also help to know which fuse you pop.

The 2G brake switch (stop switch) looks to be connected to the battery (high) side so that it's switching 12v on and off.

The typical Bosch 5 pin auto relay has two pins (85 and 86) that are connected to the relays coil and the other three pins are the normally closed (87A), normally open (87), and common (30) that the relay switches.

Since the brake switch provides 12v it needs to be connected to one side of the relays coils and the other to ground. This will cause the relay to activate when the brake switch is active. Each of the relays will draw some current when this happens from the brake circuit (as will the original brake circuit).

It looks like you have two different types of switching for the devices, one that needs 12v (high side) and the other that wants to be grounded (low side). you could make both be low side switches by providing the vacuum pump with fused 12v and use the relay to switch the ground side instead of passing the 12v through the relay.

It's critical that the brake switch only connect to the relay coil. The resistance of the coil will limit the current drawn.

 

[v8s_are_slow]

Appreciate the reply. I'll look things over and see what's what and report back.