A/C Troubleshooting

iac27

Member
Bought a 2003 t1n sprinter motorhome conversion from France and the a/c wasn't working. Got it leak tested and charged at a shop as per the specs printed under the hood. Cabin air filter also changed at that time. A/C blew coldish and not knowing what to expect I took it as normal. Since then I've gone on a few weeks of road trips (yay) and it's been slowly getting warmer and now it doesn't blow cold at all or really weak.

Did some tests today to check the aux fan and it blows strong and in the right direction when the condenser plug is unplugged. A/C clutch engages (visually confirmed). The main engine fan cannot be stopped with a card or cardboard (I may loose fingers) I used my AP200 to check as well and it says the refrigerant pressure is 58 PSI, which when comparing to another post during my research, theirs was 275 PSI. So that leads me to believe there's a leak. It did pass the leak test when I got it filled so it's a slow leak I guess. Any places that would be suspect or any ways of checking for locations of a/c leaks?

I'm planning to use some coil cleaner to clean evaporator and condenser as well just waiting for the can to arrive.

One other thing, I have a fan in the back of the RV that has a blower and button that says AC on it as well. Underneath the truck I have this device. Is there anyway to know if it's actually part of the AC system and would that change the volume of refrigerant required? The fan comes on when the dash AC button is activated. The AC button at the back doesn't activate the fan. My front AC did blow a little colder when the back AC was activated leading me to believe the two are connected and the fan helped cool the refrigerant?

Here are pictures of the secondary fan underneath that blows air for the back of the camper.

Many thanks!

IMG_0304.jpg IMG_0303.jpg
 
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sassmatt72

2006 high top long, Fully converted by me
It could also be a bad pressure switch or it’s wiring (but wiring less likely as you have a reading. )
Also I’m sure you’ve read about cracked soldier joints at switching relay mounted on hvac board in dash. . .
 

iac27

Member
I'm going to take a look at the ATC board. I don't get a signal to my recirc so the board is suspect.
 

iac27

Member
Nope I don't but it would be good to know as a backup. I was going to have a look myself to see if there's any solder that needs reflowing.
 

iac27

Member
So I have the atc apart in my hands. Can’t get the knob off to access the joints. Scared to pull harder. The solder points look good by eye. Any tips? I’m doing this because the ac is blowing warm air right now. I haven’t had intermittent problems just a steady decrease in power....
 

Midwestdrifter

Engineer In Residence
A steady loss in cooling output is not likely the joints. Check the pressures, and if they are low put half a can of 134A in. Another common sign of low charge is one side (passenger I think?) being much colder air out the vents.
 

iac27

Member
Would the evaporator in the pictures be my send evaporator. Is yours there as well? The Ac lines run to it.
 

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