until last week my ARB compressor worked fine using the ARB included switch--last week i tried to wire up a cool switch from 12v guy.

the switch has 3 tabs on back:
12v fused(which goes to my fusebox tied to a switched source)
Ground
accessory.

• when i wired up the switch the only thing that happened was the "on" LED illuminated. no compressor. i had voltage on both sides of the switch so i know that works.
• i believe my ground is good.
• the big 40 amp fuse was OK but i did blow the little 5 amp one in the fuse box at some point. how could that have happened((??))
• i havent' checked the relay yet. i'm going to swap it out when i get home today.
• when i wired the compressor back up using the original switch it still didn't work.

what do you electrical smarties think it could be? if it's the relay, why would it have blown? same for the 5 amp fuse. i was a dumbass and didn't disconnect the battery when i did the install-could that have done it?

help--thanks
steve

 

Well most likely you blew the fuse by touching the wire or switch against a ground. If you don't feel like disconnecting the battery then you should at least pull the fuses.

The switch you are installing should be rated at least as high as the one you replaced. I know some high current accessories like winches and guessing compressors can have a fairly high current draw even in the control circuit. If you put everything back to where it was and it still didn't work then you may have damaged the relay. Fairly easy to test it. I don't have a compressor on board but it may have a circuit breaker built-in that needs to be reset.

 

my next stop is to pep boys and try to replace the relay.

 

If you have a test light or multimeter it's easy to test the relay. When 12v is applied across pins 85 and 86, pin 30 should have continuity to pin 87. With no power across pins 85 and 86, pin 30 to pin 87 should not have continuity.

 

i have a test meter. i'll try when i get home. i was reading up on how to troubleshoot a relay.

 

Put the meter between pin 87 and ground. Should be zero when switch is off and 12v when switch is on. If not, then troubleshoot pin by pin.

Pin 30 should always have 12v. If not, the fuse or wire feed from the battery is bad.
Pin 85 should have 12v with switch on, zero with switch off. If zero with switch on, then it's the switch or the feed wire from the switch or the feed wire/fuse to the switch.
Pin 86 should show continuity to ground with switch off. Put one probe on pin 86 and other probe to chassis with switch off. If not, ground is bad either the wire or connection.
Pin 86 should have 12v with switch on. If not and pin 85 has 12v, relay is bad.
Pin 87 should have 12v with switch on. If not and pins 30, 85, and 86 have 12v, then relay is bad.

Note: Pins 85 and 86 may be reversed as the control circuit can be fed in either direction.