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Help with easy relay question...

90Pioneer

NAXJA Forum User
Location
USA
Putting in a relay to control my aux fan, in my '90 XJ, instead of running power through the switch.

Here's how I've got it set up:

30 - power from battery
86 - connecting to the white wire on the aux fan (the black wire on the fan is grounded)
85 - ground
87 - hooked up to my switch's "access on" plug
87a - hooked up to my switch's "power supply" plug

I am assuming I have one or more of these wires on the wrong plug.

When I attempt to turn it on, the switch will light up but the fan does not turn on.

What have I done wrong?

When I connect the fan to 87a, it automatically comes on.

Thanks
 
You shouldn't be connecting to both 87 and 87a.

There are two types of relays. One type has both 87 and 87a as "normally open," and both close the circuit when the relay is energized.

The other type, which is what I've encountered more often, is kind of a "switch hitter." I don't have one in front of me so I don't recall which is which, but one is "normally open" and the other is "normally closed." You can use the normally closed circuit, for example, to turn off fog lights when you switch to high beams. It sounds like the relay you have is this second type.

Is there a diagram printed on the side of the relay showing the internal circuits? Most of the ones I have seen have it right on the body. I'll try to dig one out if someone else doesn't come along with a better answer.
 
Well, I got it all worked out. My problem was I didn't have power running to my switch. Took it off the fuse box, and now it all works great!

Thanks for the help!
 
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