1984 A/C Circuit
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Intermediate
Joined: Feb 2017
Posts: 28
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1984 A/C Circuit
Hey Guys
I recently had my blower stop working on any setting other then low. So, today I replaced the blower relay with AC Delco part #15-81743. Everything seems to be working fine but, after approx 15 sec or so it snaps the AC fuse (25 amp) in the passenger side fuse box. Can somebody point me in the right direction or
tell me what else in on the AC circuit? I have a FSM so I can reference that if need be.
Thanks in advance and have a great Easter.
I recently had my blower stop working on any setting other then low. So, today I replaced the blower relay with AC Delco part #15-81743. Everything seems to be working fine but, after approx 15 sec or so it snaps the AC fuse (25 amp) in the passenger side fuse box. Can somebody point me in the right direction or
tell me what else in on the AC circuit? I have a FSM so I can reference that if need be.
Thanks in advance and have a great Easter.
Last edited by kane0021; Apr 19, 2019 at 01:31 PM.
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
The a/c circuit is on pg. 8A-130 in your FSM. If you put the function switch in the VENT position, does the fuse still blow when you turn on the ignition? If the fuse doesn't blow, can you select all of the fan speeds without blowing the fuse?
This test will tell you whether the problem is in the compressor circuit or the fan circuit.
This test will tell you whether the problem is in the compressor circuit or the fan circuit.
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
Very interesting! If the a/c works normally, and the VENT position makes no difference on blowing the fuse, it can only be that the two wires that connect to your fan speed relay coil are backwards. When the fan speed switch is in the HIGH position, the power for the fan motor does NOT go thru the a/c fuse, so the fan motor is NOT the problem! 
I can't find the electrical diagram for that relay, but the only reason for my answer is that there must be an anti-arc diode inside that ACDelco 15-81743 relay. You can test for this with a multimeter by measuring the resistance of the relay coil, then reversing the two test leads. Are the two resistances the same, or different? If they're different, your relay DOES HAVE the anti-arc diode, and you MUST reverse the two wires to the coil. By the way, having the anti-arc diode in the relay is a good thing! It's too bad ACD doesn't tell you about that, but they think you're plugging it into your 1981 Pontiac!
I can't find the electrical diagram for that relay, but the only reason for my answer is that there must be an anti-arc diode inside that ACDelco 15-81743 relay. You can test for this with a multimeter by measuring the resistance of the relay coil, then reversing the two test leads. Are the two resistances the same, or different? If they're different, your relay DOES HAVE the anti-arc diode, and you MUST reverse the two wires to the coil. By the way, having the anti-arc diode in the relay is a good thing! It's too bad ACD doesn't tell you about that, but they think you're plugging it into your 1981 Pontiac!
