Relay buzzing
Thread Starter
Intermediate
Joined: Sep 2011
Posts: 29
Likes: 0
Relay buzzing
1985 factory stock w/100K miles. I seem to have a problem with the relay attached to the air diverter valve (i think they call it). Lets start from the begining. I heard a buzzing sound from under the hood and started looking around. Thats when I put my hand on the relay attached to the air diverter valve and determined it to be cycling very fast. I have also noticed a loss of 1 mpg just recently. Anyone got any suggestions? What could be causing this and is it a problem?
Instructor
Joined: May 2012
Posts: 148
Likes: 1
It only takes two wires, power and ground to engage a relay. Id use a voltmeter and test those leads at the relay. Normally one wire will have +12v and the other grounds to trip the relay. If not it is the reverse.
More than likely the relay is being controlled by the ECM, so that could have a bad driver or it could be in the wiring.
If you are unable to test things pop in a new relay and cross your fingers.
Hope that helps
Regards,
More than likely the relay is being controlled by the ECM, so that could have a bad driver or it could be in the wiring.
If you are unable to test things pop in a new relay and cross your fingers.
Hope that helps
Regards,
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I have an '86, so this applies to my car. Yours might be different (see below).
On my car there are two A.I.R. vacuum solenoids. One is gray and the other is black. The connectors are keyed differently and a gray connector plugs into the gray solenoid and a black connector plugs into the gray solenoid. The solenoids are NOT sold separately and you have to buy the whole valve assembly -- except there aren't any left. When my solenoid failed I found a similar valve for some other GM car and bought it. I took the solenoid off and put it on my valve. In my case the color of the solenoid is a key factor on what fits and what doesn't.
That said, I believe I think I recall that the earlier cars ('84 or '85, not sure) use the same vacuum solenoid for both A.I.R. valves. You can tell by looking at the color of the connectors/solenoids.
THAT said, the solenoids are controlled by the ECM. Try unplugging the connector from the buzzing solenoid and see if the buzzing stops. As for what could be causing the buzzing, it could be low voltage at the solenoid (should be around 12 volts -- unplug the connector and measure the voltage with ignition on) or the solenoid itself could be bad. My solenoids measure 35 and 37 ohms, so something in that area is good. If this all checks out then you could have a wiring/connector problem or a bad quad driver in your ECM. I suppose it's possible that the ECM is seeing some weird condition that's causing it to freak out and turn the solenoid on and off rapidly. Pull codes and reset the ECM to see how that affects the problem.
On my car there are two A.I.R. vacuum solenoids. One is gray and the other is black. The connectors are keyed differently and a gray connector plugs into the gray solenoid and a black connector plugs into the gray solenoid. The solenoids are NOT sold separately and you have to buy the whole valve assembly -- except there aren't any left. When my solenoid failed I found a similar valve for some other GM car and bought it. I took the solenoid off and put it on my valve. In my case the color of the solenoid is a key factor on what fits and what doesn't.
That said, I believe I think I recall that the earlier cars ('84 or '85, not sure) use the same vacuum solenoid for both A.I.R. valves. You can tell by looking at the color of the connectors/solenoids.
THAT said, the solenoids are controlled by the ECM. Try unplugging the connector from the buzzing solenoid and see if the buzzing stops. As for what could be causing the buzzing, it could be low voltage at the solenoid (should be around 12 volts -- unplug the connector and measure the voltage with ignition on) or the solenoid itself could be bad. My solenoids measure 35 and 37 ohms, so something in that area is good. If this all checks out then you could have a wiring/connector problem or a bad quad driver in your ECM. I suppose it's possible that the ECM is seeing some weird condition that's causing it to freak out and turn the solenoid on and off rapidly. Pull codes and reset the ECM to see how that affects the problem.
