A/C Amplifier Pin #7
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A/C Amplifier Pin #7
Just installed a new A/C amplifier, A/C Compressor, Receiver/dryer. Pin #7 is the pin that is supposed to send 12V+ to the A/C compressor clutch to engage it. The wire going from Pin #7 behind the dash has been traced and has resistance as well as continuity. Is there something else from maybe a sensor that is causing the amplifier to not send power to the A/C compressor clutch??? I have a back up New A/C Amplifier I will try tomorrow to see if the New one I installed was defective. Also we put a jumper from the Positive post on the battery to the A/C compressor just to test the compressor and it all works. We are just trying to get it to all work normally from the Controls to the A/C Amplifier to the A/C Compressor. Thanks, Picture/diagram below.
Last edited by yngbuck19; 08-12-2017 at 08:01 PM. Reason: Inserting picture
#2
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What do the Manifold gauges read ??
All the criteria needs to meet before the AC amplifier will engage the clutch
Pressure to high or to Low will keep the clutch from getting voltage .
It could be poor connections
Failed sensors
bad switch
something not hooked up
Just what are you working on?
You have to look at the complete AC circuit diagram to figure why things are not working
All the criteria needs to meet before the AC amplifier will engage the clutch
Pressure to high or to Low will keep the clutch from getting voltage .
It could be poor connections
Failed sensors
bad switch
something not hooked up
Just what are you working on?
You have to look at the complete AC circuit diagram to figure why things are not working
#3
What do the Manifold gauges read ??
All the criteria needs to meet before the AC amplifier will engage the clutch
Pressure to high or to Low will keep the clutch from getting voltage .
It could be poor connections
Failed sensors
bad switch
something not hooked up
Just what are you working on?
You have to look at the complete AC circuit diagram to figure why things are not working
All the criteria needs to meet before the AC amplifier will engage the clutch
Pressure to high or to Low will keep the clutch from getting voltage .
It could be poor connections
Failed sensors
bad switch
something not hooked up
Just what are you working on?
You have to look at the complete AC circuit diagram to figure why things are not working
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This should help: http://web.archive.org/web/201204270...ditioning.html
Note that pin 6 is the ignition pulse (the compressor won't engage with the engine not running). It's just a pulse, so it is possible that your voltmeter would only show 0v at idle. You need that pulse, as well as the appropriate signal from the thermistor and the pressure switch.
Note that pin 6 is the ignition pulse (the compressor won't engage with the engine not running). It's just a pulse, so it is possible that your voltmeter would only show 0v at idle. You need that pulse, as well as the appropriate signal from the thermistor and the pressure switch.
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Everything was hooked up and charged after the new parts were installed before we tested anything. My buddy works at a shop that has the A/C machine that Evacuated the system for 30 mins then charged the system precisely afterwards. Then when the A/C compressor would not come on with the normal controls on the dash that is when we used alligator clips to power on the A/C compressor which worked and blew cold air into the cab. That is when he started wire chasing VIA ALLDATA and continuity/ resistance checks from the A/C compressor to the A/C amplifier.
I cannot remember what the gauges were reading but honestly my buddy said, "They were within spec for a truck that was idling." the high side was a little high because it was idling he said and the condenser wasn't getting the normal flow so he said that was ok.
I cannot remember what the gauges were reading but honestly my buddy said, "They were within spec for a truck that was idling." the high side was a little high because it was idling he said and the condenser wasn't getting the normal flow so he said that was ok.
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As I said, pin 6 is the ignition pulse, and your test shows 0v. According to the manual, http://web.archive.org/web/201102052...ng/22airco.pdf you should get 10-14v with the engine running.
Also, pin 8 is ground, and your measurements show (I think) 10v. That obviously is incorrect; I'd start there.
But, pin 4 goes to the A/C switch, and your notes show NO connection there. The manual I've linked is for a '93, but this sort of wiring doesn't change much with the years. Alas, you may the one to discover that it does.
Good luck!
Also, pin 8 is ground, and your measurements show (I think) 10v. That obviously is incorrect; I'd start there.
But, pin 4 goes to the A/C switch, and your notes show NO connection there. The manual I've linked is for a '93, but this sort of wiring doesn't change much with the years. Alas, you may the one to discover that it does.
Good luck!
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As I said, pin 6 is the ignition pulse, and your test shows 0v. According to the manual, http://web.archive.org/web/201102052...ng/22airco.pdf you should get 10-14v with the engine running.
Also, pin 8 is ground, and your measurements show (I think) 10v. That obviously is incorrect; I'd start there.
But, pin 4 goes to the A/C switch, and your notes show NO connection there. The manual I've linked is for a '93, but this sort of wiring doesn't change much with the years. Alas, you may the one to discover that it does.
Good luck!
Also, pin 8 is ground, and your measurements show (I think) 10v. That obviously is incorrect; I'd start there.
But, pin 4 goes to the A/C switch, and your notes show NO connection there. The manual I've linked is for a '93, but this sort of wiring doesn't change much with the years. Alas, you may the one to discover that it does.
Good luck!
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Forgot to add this pic with some more info of the conditions being produced.
My buddy says we may have a crossed wire and a possibly a bad thermistor
My buddy says we may have a crossed wire and a possibly a bad thermistor
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Careful, though. On most digital multimeters, "0L" (which is arguably short for over-load?) means the "resistance is too high" ... for this range! In automotive, we're usually just looking for continuity, 0L on any range means "open," and that's good enough. The thermistor runs from about 1.5k ohms (room temp) to 5k ohms (really cold). If you had your multimeter set to the 200 ohm range (our favorite $7 multimeter has that range), then a within-spec 1.5k ohms would read 0L.
So re-do your thermistor test, just to be sure.