98 ex cab, 5.9, laramie- AC voltage to compressor
#1
98 ex cab, 5.9, laramie- AC voltage to compressor
I read as many threads pertaining to ac issues on the 2g ram. I couldnt find what I needed. I prob didnt search right, but I found only a couple threads for 2g ram ac stuff. That right there makes me think I didnt search right, only finding a couple things. I assume theres way more than that.
In the search I tried about 4 things. 1 was "no voltage at ac compressor", "AC not working", "no power at ac compressor", "ac not working", and couple other ones like that. All I got in results were about 2 threads. They didnt help my prob all the way. Some, but not enough for my sit.
The only thing I got going on with mine is that when I turn on the ac, nothing happens but same warm air. Problem is the compressor isnt clicking or coming on. I can turn clutch plate at compressor by hand fine. The 2 wires coming from truck side, before pigtail plug-in to compressor, neither is showing voltage. Like nothing, zero. The pressure switch at the line above right there where compressor plug is does show voltage. Like 3 or 4, I forgot. But shows.
I swapped horn relay w known good one(s).
There anything I should do next, like in an "order", versus random troubleshooting out of a sequence? I do have gauges. Do have all tools to do anything. Thx for any help, Summer's Comin!
In the search I tried about 4 things. 1 was "no voltage at ac compressor", "AC not working", "no power at ac compressor", "ac not working", and couple other ones like that. All I got in results were about 2 threads. They didnt help my prob all the way. Some, but not enough for my sit.
The only thing I got going on with mine is that when I turn on the ac, nothing happens but same warm air. Problem is the compressor isnt clicking or coming on. I can turn clutch plate at compressor by hand fine. The 2 wires coming from truck side, before pigtail plug-in to compressor, neither is showing voltage. Like nothing, zero. The pressure switch at the line above right there where compressor plug is does show voltage. Like 3 or 4, I forgot. But shows.
I swapped horn relay w known good one(s).
There anything I should do next, like in an "order", versus random troubleshooting out of a sequence? I do have gauges. Do have all tools to do anything. Thx for any help, Summer's Comin!
#2
Quite the optimist. Cold and windy here.
The a/c compressor gets power from the a/c relay. The switches are not in that circuit at all.
When you set the vent control to some flavor of cooling, it sends a voltage to the PCM, to let it know you actually WANT the a/c compressor to run. That circuit divides at splice 120, to send voltage to the pressure switches, those are wired in series, and if both switches are closed, the PCM will see a voltage that tells it to trip the A/C relay.
I think the first thing I would try, would be to jumper the low pressure switch, and see if the compressor didn't run. If not, try the high pressure switch. See what happens.
The a/c compressor gets power from the a/c relay. The switches are not in that circuit at all.
When you set the vent control to some flavor of cooling, it sends a voltage to the PCM, to let it know you actually WANT the a/c compressor to run. That circuit divides at splice 120, to send voltage to the pressure switches, those are wired in series, and if both switches are closed, the PCM will see a voltage that tells it to trip the A/C relay.
I think the first thing I would try, would be to jumper the low pressure switch, and see if the compressor didn't run. If not, try the high pressure switch. See what happens.
#3
Quite the optimist. Cold and windy here.
The a/c compressor gets power from the a/c relay. The switches are not in that circuit at all.
When you set the vent control to some flavor of cooling, it sends a voltage to the PCM, to let it know you actually WANT the a/c compressor to run. That circuit divides at splice 120, to send voltage to the pressure switches, those are wired in series, and if both switches are closed, the PCM will see a voltage that tells it to trip the A/C relay.
I think the first thing I would try, would be to jumper the low pressure switch, and see if the compressor didn't run. If not, try the high pressure switch. See what happens.
The a/c compressor gets power from the a/c relay. The switches are not in that circuit at all.
When you set the vent control to some flavor of cooling, it sends a voltage to the PCM, to let it know you actually WANT the a/c compressor to run. That circuit divides at splice 120, to send voltage to the pressure switches, those are wired in series, and if both switches are closed, the PCM will see a voltage that tells it to trip the A/C relay.
I think the first thing I would try, would be to jumper the low pressure switch, and see if the compressor didn't run. If not, try the high pressure switch. See what happens.
2nd, - Un plug the low pressure switch, hook up a set of gauges and verify that there is a minimum of 45 to 50 psi refrigerant pressure, test for continuity on the low pressure
switch. 45 psi and above should be continuity - 25 psi and below no continuity.
If below 45 psi jumper the connector, start the engine and see if it will force the compressor to run.
Last edited by Ramchu; 02-25-2018 at 08:28 AM.
#4
Hot! Gets hotter. Waitll August, I'll be considering movin up North!!(specially if wifey dont start cookin better for me!)(she said she's considerin goin if I didnt start takin her out to eat more!)
Goin off on rants, sorry.
Can I ohm out the 2 pressure switches? Or u want jumper the compressor 1st? Like, before anything.
Other question, if no freon, would that cause no voltage at compressor plug?
Goin off on rants, sorry.
Can I ohm out the 2 pressure switches? Or u want jumper the compressor 1st? Like, before anything.
Other question, if no freon, would that cause no voltage at compressor plug?
Last edited by marcpilot1; 02-25-2018 at 09:55 AM.
#5
You can check continuity on the switches first
High pressure switch should have continuity at all times unless it is seeing high pressure exceeding it set limit.
Same on the low pressure switch unless it is seeing pressure below its set limit.
If low or no freon then the low pressure switch will trip and stop the current flow(voltage) to the compressor.
High pressure switch should have continuity at all times unless it is seeing high pressure exceeding it set limit.
Same on the low pressure switch unless it is seeing pressure below its set limit.
If low or no freon then the low pressure switch will trip and stop the current flow(voltage) to the compressor.
#6
Oh, ok. Checked cont on hi pr switch last night, there was nothing. But was just a quick check cuz I wanted to do at least something before I came in for the night. But I'll get more into it today. Thanks!
I wanted to jumper comprsr but then couldnt figure out the exact 2 locations to jumper it from. Assume at relay #30 and but the other end I wasnt sure. Just didnt wanna create more probs till I figured out the exact 2 locations to jumper it off to check comprsser.
On my other cars I used 87 and 30(I think those are the 2 #'s) at ac clutch relay, with paper clip horseshoe. But those are all Sebriung convertibles.
I wanted to jumper comprsr but then couldnt figure out the exact 2 locations to jumper it from. Assume at relay #30 and but the other end I wasnt sure. Just didnt wanna create more probs till I figured out the exact 2 locations to jumper it off to check comprsser.
On my other cars I used 87 and 30(I think those are the 2 #'s) at ac clutch relay, with paper clip horseshoe. But those are all Sebriung convertibles.
Last edited by marcpilot1; 02-26-2018 at 09:41 AM.
#7
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Just adding freon may get you by for a while, but keep in mind as the freon leaks out so does the compressor oil, and you run the risk of compressor failure and contamination of the rest of the AC system.
It's your call....... but I would advise to get it done properly.