Chassis AC Compressor not engaging

[Eric M]

Hello, i have a problem.  My Chassis AC on my 1996 Monaco Windsor's compressor is not activating. 

i have a few ideas on getting a voltage meter, to hook it up to the clutch enabler to see if power is coming to that, while the engine is on. i will check that

are their any other ideas i could try?

 

[Ivan K]

The clutch will not activate if refrigerant pressure is low. If you know where your pressure switch is, you might check that it closes when you turn AC on. If not, the pressure is too low or the switch is bad. If you momentarily jump it, the compressor should engage.

[DavidL]

Agree with Ivan K...Low freon is much higher odds.  You can verify that by finding the low pressure cutoff switch and seeing of it's closed or open with a multimeter.  If you short the cutoff switch and the compressor clutch engages, than low freon even more likely.  Don't do this for more than a few seconds or you could fry the compressor.

Or, get a set of AC gauges and see if there is freon in the system.  If it's low then there is a leak that has to be fixed before adding more freon.  If its a really slow leak, add some freon dye into the system to aid in determining leak location.  Look for dirt at fittings as the oil in the freon attracts dirt.  A telltale of the leak location.

If the system is empty, you will also need a vacuum pump to evacuate the system of moisture before adding back the freon to the specified qty.  You can also determine if there is a moderate to large leak by stopping the pump and looking at the gauges for a few hours to determine if there is a leak.

 

Bottom line, invest in the right tools and learn, or hire a pro.

Edited June 15, 2020 by DavidL

[Eric M]

i need to find a R-12 meter. 

[Ivan K]

Any gauges will do, just need the correct fittings for whatever you have. Cheap HF gauges will work for R12 as well as R134, until the hoses fall apart eventually... Are you sure you have R12 in it? That might be hard to find for refill and you may have to convert to R134a. I still have R12 for classic cars but it is priced as gold these days...

[Hypoxia]

1996 had R134 refrigerant.  The other posters have mentioned the cheapest, fastest way to check the compressor operation; find the low pressure switch, unplug it and jumper across the plug.  If the compressor clutch engages then it is likely low on refrigerant but there are other possibilities.  You can run your generator and house A/C for years and not burn as much fuel dollars as one A/C repair bill.

[DavidL]

Buy a set of gauges and a vacuum pump.  Harbor Freight is fine for limited use.  Then see if the fittings attach to your RV fittings.  If not, then you might need to get an R134 retrofit kit.  You cannot refill with R12 if it is R12 but it's likely R134.  If R12, then the system has to be vacuumed down for a few hours.

[Ivan K]

I think the  last year for OE use of R12 was 1994, legally. Just because you may have same as R12 type fittings does not mean much. Ours does too. Check your manual, it should mention what was used. Maybe a label on the compressor, if present. "Correctly" done retrofit would involve much more than just freon change but I doubt you'll have R12, R134 is cheap if you end up needing it.

[Eric M]

I vaccumed down what i had, left it under vaccum for about 8 hours.

turned it on again, got whatever was left in there, out. Refilled with the PAG oil, with the ICE additive to make it colder. then, added a "stop leak" additive to hopefully seal up, whatever was leaking in the system that brought my refrigerant pressure to.... about 8 LBS. 

 

under vaccum, it didnt leak. so it may have been the elevation change from it being charged at sea level, to being taken up to 5,000 FT (colorado) and i hasnt been ran the whole trip. (drove here in December, no need for AC then)

so.... CASE CLOSED! 😘

[DavidL]

Good to hear the system is working again.

For future purposes and for readers, never use "Stop Leak".  It gums up the system.  If there is a leak, one has to find it, fix it,  vac and recharge.  There are no short cuts other than different tools and fluids (UV dye) to help find the leak.

[Eric M]

my system pipes are.... HUUUUGE. so im not worried about it.

the "STOP LEAK" also contains a dye.  that if it cannot be sealed, it will expose it, so you can seal it manually.

it seals the gaskets and stuff, the small,little seals. 

my ASE certified for automotive, trucks, RV's, 18 wheeler trucks. said that this "stop leak" seals at the exposure point only. 

i got a guy helping me, that makes $175,000 a year fixing Ford's and other vehicles.  He knows what he is doing.

 

 

 

 

Edited June 21, 2020 by Eric M

[Ivan K]

It's not the hoses that get gummed up, and you won't be able to suck it out, too late now anyway. But you should be ok if it won't leak out dry and use it once a while. Just watch it.

[Hypoxia]

16 hours ago, Ivan K said:

It's not the hoses that get gummed up, and you won't be able to suck it out, too late now anyway. But you should be ok if it won't leak out dry and use it once a while. Just watch it.

I've been in A/C parts places which have parts on display which are completely plugged with stop leak.  I don't use that stuff either.

[walt2137]

On 6/21/2020 at 12:41 PM, Eric M said:

my system pipes are.... HUUUUGE. so im not worried about it.

the "STOP LEAK" also contains a dye.  that if it cannot be sealed, it will expose it, so you can seal it manually.

it seals the gaskets and stuff, the small,little seals. 

my ASE certified for automotive, trucks, RV's, 18 wheeler trucks. said that this "stop leak" seals at the exposure point only. 

i got a guy helping me, that makes $175,000 a year fixing Ford's and other vehicles.  He knows what he is doing.

 

Eric hope you have good luck especially since you used a stop leak, my 2000 Dyn has the expansion valve insted of a orfice

tube on the AC system, i dont know what your 96 has but assume it has a expansion valve and if so its a good chance the stop leak

will plug it up (its up front on the fire wall) if its a orfice tube they dont generly plug.

 

 

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Edited June 23, 2020 by walt2137

[Eric M]

i have an oriface tube. and it hasnt clogged.