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You're not just putting refrigerant in Willy-nilly, with no gauges or knowledge, are you?
No, I used a simple R134a refill can with a separate/connected gauge on the Schrader valve to check pressure (I first released some freon, just before jumping the A/C clutch relay, to see if there was some present). Then started engine and turned on the A/C, as if to top-up like on my other cars, then jumped the A/C clutch relay. the system sucked in the 1/2 can I had, then another 1/4 can I switched to, with the gauge finally resting at 35. Like I said, the vent temperature read 38f, the engine temp settled at 181f, and the radiator fan as engaged while the paper-clip jumper was in place. I removed the clip, and the fan stopped, so I shut it down.
After that, I let the HHR rest for a few hours, replaced the A/C relay, and started it up again. Still, no clutch engagement. I quit at that point, so I could pull out my defunct clothes dryer in prep for the new delivery (which I opted to haul and set-up myself), and later wired/connected the new one. My back (and knees) was done for the next two days.
I have put two 3/4" treated plywood 4x8 boards down in my sandy driveway, as a stable working platform for my ramps/jacks/etc. in preparing to do the Cobalt M/C and ABS overhaul (so I can get under it safely, with no assistance from my non-existent helper). I'll have to get a new battery to move the Cobalt out of the way, first, then I can ramp-up the HHR to resume working on the A/C first. I just can't crawl under it anymore, to test or replace the pressure switch. I hope there's a Schrader valve between it and the line, so I can put a new one in myself, or off to a shop it goes. I'm ordering a gauge set and a pressure switch today, getting a battery Monday.
That’s not a switch, it’s a sensor, apparently a simple variable resistor from which the ECM is using two analog values to determine if it’s OK to run the compressor. Maybe there’s no jumper configuration that would result in an acceptable condition. Even if you knew what the proper ranges were it seems like it would be a lot of trouble to test the sensor, and a bit of trouble to R&R it. I would think both too low and too high pressure would make starting the compressor a no? A bad sensor would explain things. I’ve never checked if my scanner will tell me refrigerant pressure. Someone who know something about auto a/c will know what a normal pressure range is, and that’s not me.
Originally Posted by donbrew
Use your paper clip to jumper the pressure switch? There is a diode in the fuse box that would be easy to check.
items checked vs possible their possible link to persistent problem
Originally Posted by PulpFriction
That’s not a switch, it’s a sensor, apparently a simple variable resistor from which the ECM is using two analog values to determine if it’s OK to run the compressor. Maybe there’s no jumper configuration that would result in an acceptable condition. Even if you knew what the proper ranges were it seems like it would be a lot of trouble to test the sensor, and a bit of trouble to R&R it. I would think both too low and too high pressure would make starting the compressor a no? A bad sensor would explain things. I’ve never checked if my scanner will tell me refrigerant pressure. Someone who know something about auto a/c will know what a normal pressure range is, and that’s not me.
I've never claimed to know A/C systems, even back in the day, or even in GM Tech school in '71-72. I'm just trying to follow suggestions from others that know more than I, as best I can.
The diagnostic rundown sequence, as I see it:
1) A/C clutch stopped working at SAME time the near-overheating of the engine coolant,
2) no codes were set (not even for possible P0128); relays swapped, diodes also, "codes" cleared anyway,
3) refilled w/new coolant to test for t-stat problems, and/or temp sensor tie-in with A/C or possible overheat,
4) four months of driving tests of the cooling system proved it was OK (typical coolant temp range from 180f-195f, tested the automatic radiator fan cut-in at 217f, when stopped-in gear-at home), but though the A/C control provided heat, the A/C clutch still was never engaged,
5) tested A/C line for pressure before jumpering the A/C clutch to run,
6) A/C sucked in nearly 12 ounces of refrigerant, cooled at vent to 38f (80f ambient), engine temp steadied at 181f, fan came on when control turned on,
7) replaced jumper with relay, A/C clutch ceased operation.
8) I can't see how I can properly reset "faulty" pressure sensor/switch unless a variable resistor is used...not in my toolkit, nor in my "wheelhouse" as they say
9) Next steps
a) pull the main fuse near the battery, for 1/2 hour (some say it'll reset everything, even better than the PCM fuse,
b) try out my bi-directional scanner for the first time, perhaps it'll be able to manipulate the clutch,
c) replace the pressure sensor/switch with a new one (I sure hope there's a Schrader valve beneath it), d) save my pennies for a replacement HVAC dash control unit (about $230 USD)....
You can't even say what the high/low pressures are. I would say...
9) Next step - take it to a pro.
Originally Posted by working on it
I'm ordering a gauge set and a pressure switch today, getting a battery Monday.
Forgot the above quote from a previous post...it should be step 9a, and the replacement sensor/switch would be 9b.
I'm determined to at least try to fix the HHR, while I'm not so sure about my ability concerning the MC replacement (+ maybe the ABS unit, too) on the Cobalt. After the expenses we've had lately, the HHR may suffer the consequences (put aside, wait for later).
The "on" signal for the compressor comes on a wire directly from the BCM. Inputs used by the BCM are the button on the dash, the fresh air control, the mode control the pressure switch. I guess that narrows it down to the computer. (sarcasm).
Ebay has used control panels starting at $22.50. One of the members parting out cars could probably beat that. GM pressure switches on Amazon go for around $20. $45 and 15 minutes would replace everything but the compressor pressure circuit.
The "on" signal for the compressor comes on a wire directly from the BCM. Inputs used by the BCM are the button on the dash, the fresh air control, the mode control the pressure switch. I guess that narrows it down to the computer. (sarcasm)....
* Yep, it was. Almost six months after the A/C compressor stopped working (except when jumpered), my HHR Panel is now ready for summer.
* I've had many things (broken this, needs-help that) pop-up in front of working on my HHR Panel's A/C problem. Acquiring tools (final tool was a true manifold gauge set) wasn't done until the weekend before I worked on my squareback trailer, prior to a long trip out of town in it. Then it rained for days. Then the clothes dryer started acting up, and after three days of trying to fix it (21 years old Amana), I gave up and bought & installed a new dryer. Then it rained for days. Then the wife's GMC pickup started acting up, again. Already had a new cap & rotor, so it got new plugs & plug wires (10 years on them), and replaced a PCV valve that wouldn't clean-up. Rain again.
* Next, started preparing my old 18 ft. (dovetailed, steel deck ) car-hauler to trade it to a friend (for his 5x12), today. We had removed the five flats from it a week prior, and he returned with three good used, and two new tires on my old wheels. Just before he was to arrive, I finally tried the NT510 scanner on the HHR...in less than fifteen minutes I had activated the bi-directional controls for the A/C relay, radiator fan, A/C control, to test, and voila the A/C was fixed! Compressor running and all (cooled to 36 degrees!). I disconnected the scan-tool, and proudly showed it to my friend as he arrived.
* After the tires/wheels were on, he asked to see what I'd done with the scan-tool to fix the A/C, so I showed him. He said he could use one like it on his BMW, Subaru, Kia, etc. It was a good deal, for $180 (including GM programming...other makes' programs are available for $60-80). I just couldn't afford US-labeled bi-directional scanners (probably all made in China anyway). After he left, I returned several times to the HHR, to turn the A/C on-off, just to prove to myself that it REALLY was working.
* The scanner's "freeze frame" also showed me when the A/C went off, at what coolant temperature, and several other parameters. I should've saved that screen, but hit the wrong button (first time usage). It also showed hi-side/lo-side pressures (OK) and a lot of other parameters, but by that time it was already fixed, so I just backed out, and worked on the trailer.
* I never bought an E-bay A/C control, or an Amazon ACDelco pressure switch. Nearly ordered both this morning, but something told me to "just try the scan-tool first". Glad I did. Thanks to all for the guidance, and now I'll have all the A/C tools ready for a future occurrence, if any comes, on all my vehicles.
Ok. I always seem to have an excuse for not following the sage advice given, especially where electronics are involved. Any technology advanced enough does seem like magic to me. At work, though not auto related, I usually figured a work-around to bypass faulty programming, since I had no training in that. On my cars, I avoided delving into electronics repair, and fired the parts cannon instead. Usually successful, but the HHR problem seemed weird. Not the T-stat, nor the temp sensor, nor the fuses, diodes, relays, or A/C clutch were bad. Everything I read pointed to resetting the BCM by removing power, after my older scanner had reset dtc's. No dice. So, I was going to give it one last try with the new scanner, before I fired the parts cannon again. It worked. Like magic. No smoke leaked out, either. Thanks again.
