Today's project involves connecting two standard 40 amp auto relays in series.

It looks like this...

(wire from + power and switch)----relay 1 coil terminals---relay 2 coil terminals...ground.

The idea is is that when the switch is thrown, relay 1 and relay 2 will activate. And indeed, this is what happened when I tested them in the garage.

Took it out for a test drive. On the first activation, the relays both closed. On the second and succeeding attempts, the relays did not close.

Back in the garage. Put a meter on the relay one "input" coil terminal and throw the switch. I get 12 volts, as expected.

Put the meter on the relay one "output" coil terminal...I get 6 volts. What???

Should I have wired these in parallel?

Thanks,

John
1987 XJ-S V12

 

Yes, The two coils in series will have a voltage drop, roughly equal between +12 the earth ground. That also assumes the coils are both rated for 12 volts and the resistance of each coil is the same.

 

Well, that's about what I'm experiencing. I'll put them in parallel and see if that doesn't fix it.

Thanks!

John