A/C fan(blower) relay question

[SHOerwin]

Haven't posted in some time, but I have an issue right now that has me puzzled. The relay, or breaker, or whatever it's called, keeps blowing. This prevents me from using the a/c, heater, defroster, vent, et al. Quite annoying in the rain! I haven't put 100 miles on the car since moving to Georgia in May. I have replaced said unit 7 times. Every single time, the fan will work for about 2 minutes before the just-replaced piece expires.

Any clues?

Thanks, Jono.

 

[SHOZ123]

This is the relay under the hood?

 

[SHOerwin]

Yes sir. In the box at the front. It's square.

 

[SHOZ123]

Have you ran the EATC code retrieval procedure?

 

[SHOerwin]

No sir. Is that the one where you hold some sequence of buttons, or is it with the code-reader?

 

[SHOZ123]

http://v8sho.com/SHO/EATCandMaxAC.htm

Will tell you how to do it and what the numbers spit out mean.

Is the blower running on high speed only?

 

[SHOerwin]

It doesn't run at all. The compressor runs, the temp will show, and even the fan level readout will change as you increase/decrease. But no air will blow out of the vents. I could put another relay in right now, and in about two minutes it would be dead again.

 

[SHOZ123]

Is the connector where the relay plugs in burnt? I burnt up a relay once running the fan on high in very hot weather.

I see no reason for a relay to burn up unless there is a lot of resistance on the load side connectors. Maybe the wire is loose or corroded at the motor end too. But to burn up the relay would take a lot of amps.

Are you using a 40A relay or a cheap 20/30 amp relay?

 

[SHOerwin]

The part number I have been using is MR76. I have been buying them from NAPA and Advanced. I did the test, and the readout read 888.

I don't know what the amps are on MR76, but my gut is telling me it's 20-30. If I recvd the lower amp relay as a replacement for the factory piece, and used that number for all subsequent replacements, then I've been wasting cash and time.

 

[SHOerwin]

I'm going to check the relay panel right now for any sign of burning.