OlympicMtnBoy Posted June 24, 2009 Share Posted June 24, 2009 Hello All, The previous owner of my little Chinook disconnected the belt on the A/C compressor a few years ago and I'm trying to get it up and running again (it supposedly was working) before a trip to Yosemite in a few weeks. I hooked the belt back up and things seemed to work but the compressor wouldn't run unless you got under the hood and forced it. Figured might be the low pressure switch since the coolant probably leaked out with the disuse. $250 later from the A/C shop for a R12 recharge and A/C "service" and they say it's leak free and fully charged, but there is a control problem they can't get the parts to fix. They said the low pressure switch is fine, but the circuit that is supposed to power the compressor when the engine hits a certain rpm is not kicking in. They suggested wiring a toggle switch into the cab to just turn the compressor on and off manually. It has proper pressure and gets nice and cold when running. Anyone have suggestions? Is there a way to fix this for real instead of bypass it? Will I burn up my compressor or something if I accidentally have it on with low engine rpm? If I do a switch obviously I should take power from something that only runs with the engine on, any good circuits I should tap for this? I'm pretty much a novice, but I figure I can wire a switch easily enough and I had them show me what terminal needs power. Thanks, Stewart P.S. Posted this on the yahoo group too, not sure how many people read which one or both. :-) Quote Link to comment Share on other sites More sharing options...
OlympicMtnBoy Posted June 24, 2009 Author Share Posted June 24, 2009 Problem solved! I just learned something new and fixed my problem the super easy way (the way that Toyota designed it)! I didn't have any bad switches or anything, no need for a toggle either. I just traced the wire that was supposed to be powering the compressor through the firewall and stuck my head under the dash. The wire disappeared into a complex looking box bolted on the A/C unit with a bunch of other wires running in and out. On the box was a little knob labeled "rpm". It was set to one extreme end. I turned it the other way and now the compressor turns on with normal engine rpm and she blows nice and cool! Apparently the A/C folks I took her to today didn't bother to look under the dash mounted A/C unit. So if you're stuck with the compressor not turning on, or only engaging at very high rpm, check that little dial first! I'm so happy not to have to rig some mickey mouse random switch or pay the shop any more! - Stewart Quote Link to comment Share on other sites More sharing options...
Supurcar Posted June 25, 2009 Share Posted June 25, 2009 Can you post a picture of what you are talking about? I would go back and get a refund from the mechanic that charged you $250.00. My A/C just needed some freon and of course the mechanic says I need a whole new compressor. I charged it and it works fine, I think they have a minimum they will work for and try to create work. I bet you did not need to "service" the unit at all or pay $250 for about $40 worth of freon. Quote Link to comment Share on other sites More sharing options...
OlympicMtnBoy Posted June 25, 2009 Author Share Posted June 25, 2009 Can you post a picture of what you are talking about? I would go back and get a refund from the mechanic that charged you $250.00. My A/C just needed some freon and of course the mechanic says I need a whole new compressor. I charged it and it works fine, I think they have a minimum they will work for and try to create work. I bet you did not need to "service" the unit at all or pay $250 for about $40 worth of freon. I'll try to get a pic, but I'm heading to Mexico tomorrow (flying) and might not have time till I get back. Basically if you stick your head under the A/C unit in the cab you'll find a small black box on the left (towards the driver) side with a bunch of wires running into/out of it. The knob is pretty tiny and on that black control box with the letter "rpm" printed next to it. I can't blame the shop too much, not many people in Seattle do R12 anymore (had to call around), and they charge $70/lb. Based on ebay prices, I could get it for about half that, but I didn't do that ahead of time and I'm getting ready for a trip. I wanted a leak test and all that since the unit had been unused for several years, so they get me with their posted $70 A/C service fee. They only charged me $20 in labor for trying to figure out why the compressor wouldn't engage (which I would like back but don't have time to hassle, and they were pretty nice about taking time to show me what they checked and what wire needed power, etc). But yeah, I'm definitely leery of the "new compressor" gag. I also found out you can get the bearings and stuff seperately when those wear out. Cheers, Stewart Quote Link to comment Share on other sites More sharing options...
Maineah Posted June 26, 2009 Share Posted June 26, 2009 Be careful buying $40 R12 freon it may not be freon. The ideal years ago was to price R12 off the market just a different way of banning it. If you have A/C issues to deal with any way that would be the time to switch to R134. Quote Link to comment Share on other sites More sharing options...
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