I recently converted my single AC to duel AC I got all new 4 man wiring harness and all new 4 man AC lines and 2 new rear AC condensers finally got it all done and when to the AC shop verified there was no leaks pulled a vacuum twice. I did a vacuum test at home and let it sit for four days to verify. There was no leaks and the shop did another one. We charge the system to 3 pounds and there were some ounces I can’t remember the number, the front is blowing cold and the rear unit kicks on and off and I hear the relay over on the passenger seat clicking on and off along with the compressor and I’m trying to verify if it’s just because my local temperature here today is only 43° outside and the system is not getting enough pressure and warm enough for it to hold the rear evaporator on or is the AC relay different from a 2 to 4 man or is there anything else that I could check when the rear unit kicks on? I feel it blowing cold air but it shuts off and on like I said I’m not sure if it’s just cause the ambient temperature here is so cold out that it’s not gonna work properly or if there’s something else I need to check.
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4 man AC conversion
- Thread starter Slick580
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Following this thread, as my M1151A1 rear unit cycles on and off irrelivant of outside temp.
DREDnot
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Is the "relay" by the passenger seat one of two behind the battery box?
Correct but I kinda figured it out
So o had the driver side AC condenser harness plugged in wrong and after I corrected it the rear unit came on is blowing cold and not tripping the relay but now I have another issue the passenger side condenser is not coming on. I supplied power directly to each fan and they are working so now I’m wondering if the relay by the dryer is bad?? But look at the diagram I thought both condensers get power from that relay….
Have you checked the pressure on the system to make sure it’s full??
DREDnot
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The "relays" behind the battery box are actually circuit breakers that self reset when they cool down.
I believe the relay by the dryer powers both condensers. Double check your connections by number tag.
I believe the relay by the dryer powers both condensers. Double check your connections by number tag.
Correct so the driver side condenser fans are working but the passenger said is not and I checked the connections everything is correct and plugged in. I was told that the driver side gets power from another source and the passenger side is controlled by that relay that’s attached to the dryer bracket if someone can chime in and verify, I’d be awesome.
DREDnot
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Yep
same one I have issues is this is just the harness diagram this does not actually say what has power what is ground? What is the signal switch? I figured out that seven is ground and falling from the circuit breakers. According to this diagram that rear condenser relay only controls the passenger side because why would my driver side be working not my passenger side?
DREDnot
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There is also this relay inside the rear evaporator unit. Im not sure if it powers the condenser fans or just the evap blower.
This is where I'm stuck on the system I'm working on. My condenser fans stay running after shutting the system and the truck off till I unplug the cannon plug to the rear evap box
This is where I'm stuck on the system I'm working on. My condenser fans stay running after shutting the system and the truck off till I unplug the cannon plug to the rear evap box
Yep and there is one by the dryer on the passenger side we the fuel filler neck is I believe that one controls the passenger side condenser
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Not since the spring when I topped it off. My next step was going to be evacuating the system and performing a vacuum leak test.
Definitely I did that with the kit from my local parts store I ran the pump for an hr then I let it sit for a couple day while I waited to get to my buddies ac shop to get it filled
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Just a few thoughts.
Any time you evacuate a system you should replace the receiver/dryer, when in use the descant gets coated with oil and it would take a very long time under vacuum to get all the moisture out of the receiver/dryer, it is very cheap insurance.
Target vacuum should be 500 micron or less for a system with a mechanical seal.
I let my pump run all night, I also use a digital micron gauge, that minuscule swing on a typical pressure/vacuum gauge means nothing.
I generally pull a vacuum first to make sure the system is OK, then replace the receiver/dryer and evacuate again, the receiver/dryer should be replace just before pulling a vacuum.
Most do not understand the receiver/dryer is a disposable maintenance item just like an air filter or oil filter, many manufactures recommend replacing the receiver/dryer every 2-3 years, although I admit I don't replace them unless the system needs to be evacuated for any reason.
Any time you evacuate a system you should replace the receiver/dryer, when in use the descant gets coated with oil and it would take a very long time under vacuum to get all the moisture out of the receiver/dryer, it is very cheap insurance.
Target vacuum should be 500 micron or less for a system with a mechanical seal.
I let my pump run all night, I also use a digital micron gauge, that minuscule swing on a typical pressure/vacuum gauge means nothing.
I generally pull a vacuum first to make sure the system is OK, then replace the receiver/dryer and evacuate again, the receiver/dryer should be replace just before pulling a vacuum.
Most do not understand the receiver/dryer is a disposable maintenance item just like an air filter or oil filter, many manufactures recommend replacing the receiver/dryer every 2-3 years, although I admit I don't replace them unless the system needs to be evacuated for any reason.
ErikMac
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Did you ever figure this out? This is exactly the spot I'm in right now. Not sure where to turn/try next. Thanks.
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