Comp Relay problems

i can't figure it out. i have 2 Viair 450's running on 2 different 40 amp relays. the relay keeps burning up on me and i don't know why. the power wire from the comp going to the relay is the wire that is burning up causing it not to work. i put a new relay on the comp and it works fine for like 2 weeks then burns up. can some plz help on what i need to do. thanks.

what size wire do you have goin to the relays? you need at least 10 gauge...

well i have the factory comp wire going into the i think it is 12 wiring harness that is supplied with the relay.

so is that what i need to do wire a 10 to the relay?

I'm having the same problem man. the relays burn up and the compressor won't shut off with either the pressure switch or the one in the cab. I'm running a single 480 though. I seen an ad for an 80amp relay by AZ in one of the mags that I might try.

I'm thinking it just needs a bigger relay. I just put my last spare relay in tonight so I need to order me some more asap. Luckily I decided not to unhook my 380 when I upgraded so I have a backup comp and that 380 is a workhorse. too bad it's slow.

I had the same problem with my 40amps, i bought an 80amp Swinger from suicidedoors this time. I hear they do the trick i dunno yet tho. I would try nice heavy wireing and the swinger from suicidedoors.

I was having the same problem when I ran my AZs. I switched over to SR80s from Stinger and they have be perfect ever since.

30 = battery postive
85 = pressure switch
87 = compressor
86 = Ground
87a nothing

now if your running a stretch of wire from the battery in the engine compartment to the back of the truck you need a minimum of 4 gauge wire. the voltage loss in a long stretch of wire like that can be tremendous.

make sure you ground both compressors in the same location on bare metal. Preferably the frame.

Take a small run of 1/0 gauge wire and run it from the frame to the ground of the battery.

You should do the big 3 if you have other stuff like high wattage lights and a stereo.

Those little relays aren't really designed for continuous duty- if your pumps are running for a while the relays will eventually fail.
Get a larger solenoid-style relay (we carry an 85 amp continuous duty model for about 20 bucks)and run both of your pumps off of one relay, and you'll be a lot happier.
If you want to find one locally, the Napa part number is ST-87- but they're expensive.
DON'T cheap out and buy a Ford starter solenoid, because they're not designed for continuous load either- most Ford owners can attest to their starter solenoid sticking on once or twice!

-Phil at FBI

I had relays crap out and cut in and out before. I switched to a solinoid last year, and havent had a problem since