Before I get started, thanks to the forum regulars for your help - I check this forum every time I have an issue with my van and there is always useful information.

My A/C system hasn't worked since I bought my van used in 2010 (1997 Ram Van 2500 5.2L Elk conversion). I bought the van in January in Wisconsin and didn't know how to test whether the A/C would work or not (it was about 20F outside that day). Anyway, I've just been sweating it for the past two summers. I have a road trip coming up and am thinking about getting my A/C going again. I'm here to gauge how big of a project this might be (my suspicion - too big!).

Currently, the compressor/clutch does not engage when the A/C is switched on. The fuses and relays are good, both in the glovebox panel and on the power center under the hood. The A/C clutch clicked when I took some jumpers and connected it directly to the battery, so I think it is not the problem at this point.

My whole cooling system is RUSTY (see pics). The van is a conversion and has "Central Heat/Air" according to the original dealer window tag. There are hoses running to the rear passenger wheel well area, but I don't think there is a dual compressor system. The rear heat/air seems to just be a fan of some sort, but I could be wrong. I don't know how to get in there. I might like to eliminate the rear system/hoses anyway, since I seldom drive the van with more than 1-2 passengers, and it's not that hot where I live (WI).

I don't know if the system has any pressure or not, and I'm wary of doing the vent test (e.g. screwdriver on the Low side port valve) because of environmental and safety concerns. I'm wondering if there is some sort of computerized/automatic shutdown if the system doesn't have sufficient pressure, but I can't figure it out.

Should I take this to a repair shop, or is this going to be way more trouble than it's worth? The van itself isn't worth much, and I'm imagining a hefty bill if I take this thing to a shop. Any insight from the pros around here?

A/C system up front - what a mess!


The hoses going to the rear heat/air unit:

 

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Thanks for the reply, blackvan.

I will check to see if there is any pressure via the Low pressure port. (fingers crossed). Replacing the drier would be simple enough.

Any opinion on disabling the rear heat/air system that never gets used? Because of the rear system, there are at least 4 T's in the hoses (A/C in/out, heat in/out) that make the hose arrangement under the hood complicated (and probably more prone to leaks - hose clamps everywhere, I feel like Harry Tuttle from Brazil). To me it just seems like a liability - more stuff to break.

 

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I checked the Low side pressure by quickly depressing the valve - there was some pressure, just a little "psst". This give me some confidence that there is not a major leak, otherwise there wouldn't be any pressure at all.

I might try a refrigerant recharge and see where that gets me. I hope that the pressure sensor recognizes the pressure increase and lets the system fire up!

Your AC hoses look much neater than mine. I don't know how mine got so rusty - Wisconsin winter road mist, I guess. If my van makes it another few years without major mechanical problems, I'll be happy. My initial investment was quite low, so any additional miles are a bonus.

 

To update, I added some R134a with Leak Stopper additive to the system this morning. Using the full can (20 oz), I got the pressure up to about 22 psi, which is quite short of the ~35psi recommended for the current temperature (about 80F). While doing this, the compressor clutch engaged and I'm getting some cold air now. The specs on the van indicate 3.75 lb of total refrigerant, so if I was actually empty, then I'm still short by 50%. (edit: more than 50%, actually, 3.75lb = 60 oz.)

I took the van for a little drive, to see if there was any improvement with air moving over the condenser. The air blows reasonably cold, from both the front vents and the rear auxiliary system. I wouldn't say it is chilly air, but it is definitely cooling.

However, I can hear the compressor cycling on/off while I'm driving along. I can hear the clutch clicking when it engages. This happens about once every 30 seconds. I am thinking that the overall system pressure is still too low, or that the pressure at the sensor is oscillating and going into the auto-shutdown.

This happened while I was charging the system too - when you add refrigerant, the low-pressure sensor says "OK, go", so the compressor starts pumping refrigerant. When this happens, it draws down pressure in the Low side until the low-pressure sensor says "nope, kill it". Add a little more R134a and the the cycle repeats. Maybe I'm still low on refrigerant? Or maybe a more serious issue (leak, obstruction)? I didn't notice any major leaks (no hissing noises, no visible leakage of oil), but I suppose something could be sneaking out inside the evaporator box, or along the tortuous path to the rear unit. I'll keep my eye on things over the next few days.

 

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Do add more refregerant to your system. Also check the top of your dryer for a little bitty window, mine has one and most older Dodge vehicles did. That window if your has it will also tell you when the refregerant level is correct. If you see bubbles or creamy cloudy in the window add more till you see that the fluid is clear which then means you have enough in the system.