AC not blowing cold, whats the cheapest initial fix/test (98 disco)

 

Normal problem is not enough refrigerant. If you don't have a set of gauges, and you don't have a vac pump to pump down system before refill, then best to take to small AC shop. Just sticking in a can of refrigerant may overfill system, the system could be full of air now, etc. Of course, when AC on the compressor clutch needs to pull in. There are fuses, etc. But there is also a switch that keeps compressor from running wih low refrigerant. If system has been out for awhile you can expect to put in a new drier (cylinder in front of condenser)

Cheap fix is the old reliable 260 system - roll down two windows and go 60....

 

With the A/C switched on, engine running, do the A/C fans turn on?

 

yes they do.

 

is this always the case or do they run off of a pressure switch?

 

On a D1 the AC condenser fans simply come on whenever AC is switch on, no regard to pressure. If they were not running, or running backwards (like mine wired by a color blind PO), will be cool when truck is at freeway speed, but not good when idle or slow. IMHO, if you have never worked on a vehicle AC system, and don't have the tools, or can't borrow the tools, then invest a little to have it checked by a shop. Try to fill it without a gauge and you could do a lot more damage than that inspection will cost. Yes, you can learn to work on AC. It is not magic. But doing it blind without test equipment may not produce desired results.

 

I will do this. its only a 100 bucks at the shop.

 

Go buy a DIY kit at the store, $15 and you will have cold air again.

 

If you don't have any problem other than refrigerant has been lost, has not been replaced by air leaked in, etc. But if you have some other problems, and over fill system, that could be a problem. At least buy the kit that comes with a single gauge and follow instructions, and if it does not start cooling , turn AC off and take to shop. I agree with Spike that this is a first step, but usually an AC check near me is like $20, without refrigerant.

 

At least the system is on when then activated at the switch. I agree, go get a can with a gauge at the local store. I believe the new ones contain sealant and additional oil. Once system reaches the correct pressure, the compressor should start to pump and the interior temps should drop. If the gauge never reaches the correct pressure, it will not work, there is a leak in the system.