ac relay keeps blowing out

[aleminx]

the compressor coil checks out at 3.2 ohms (in spec) and I fused the front condenser fan wih a 7.5 amp. any ideas why i'm going through these $35 relays? I've gone through two already and would like to get to the bottom of the problem rather than keep throwing new relays in there. it works great for a couple of weeks and all of a sudden its dead again.

[aleminx]

sorry this is an 85 carrera 3.2 if that helps

[Dave Colangelo]

I am not familiar with this issue but some general relay things you may want to consider.

Are these the regular old square 4 or 5 prong 12V relays used for most auto applications. If they are you can get them for far less than 35$

You can protect the relay with a diode on the ground side, to prevent the coil from blowing out. What can happen with relays some times is when you shut them off, if the polarity is for some reason reversed, say ground is at a higher potential than the other side of the coil, this is like quickly reversing the voltage on an inductor. Remember these coils are made with some quite thin wire, when the voltage is quickly reversed the coil (acting like an inductor) will try and flow current against the voltage this can cause the small coil to melt and short. I dont know what the specs are on the diode but there may be some one here who knows.

This may not be the issue at all but i though it would be good to bring it up.

Regards
Dave

[DRACO A5OG]

Are you writing about the relay in the smuggler's box? If so, are you using the OEM spec relays superceded with a fuse that our Host sells?

I have noticed placing a standard relay will not work.

I had major issues with my #1 fuse panel, it over the years had developed too much resistance, swapped it with a new one and cut the tab in the back to make certain it was like the OEM and I no longer blow the #2 AC fuse.

I replaced my relay due to a buzzing noise and over heating of that relay. Replaced it with the fused one our host sells, not a peep from it.

[aleminx]

It is the circular relay in the fuse panel, not the one in the smuggler's box. as far as i know, that one is fine. Would a fuse on my fresh air blower help ?

[DRACO A5OG]

The Fresh Air Blower is on a different circuit. Strange why would the round relay pop? Hmmm. Need to look at my wiring diagram.

I wish Gerry would chime in he may know for sure, He saved my but on my AC issues.

[aleminx]

sorry, I meant "evaporator blower" not "fresh air blower" I have been thinking of fusing this because I seem to recall reading somewhere that it is wired directly to the relay which handles a couple of other things as well... might be overload since it is 25 years old?

[DRACO A5OG]

Oh in that case, YES, I highly suggest adding that inline fuse, on the hot lead.

As far as the relay, check the contacts on the relay socket, clean and polish them to see if that will reduce the resistance on that socket.

[aleminx]

any suggestions for fuse size?

[86 911 Targa]

Originally Posted by aleminx

any suggestions for fuse size?

Try this from our host.

However, we need to find out why the relay/fuse is blowing.

Do you have a multi meter, and the circuit diagram?

Good luck,

Gerry