1999 V70na Trouble shooting A/C--where to begin?

paredown · Post by **paredown** » 31 May 2015, 14:32

We have some trips to make this summer, and we decided we can't stand doing any road trips once the heat gets going. So even though I dread the thought, it is time to think about A/C.

What I know:
-I replaced the heater core when I did the triage repairs when we first got it, so heat is OK
-Accessory belt was replaced when I did the timing belt
-I have not checked the clutch gap
-I do have the infamous flashing A/C and RECIRCULATE 20 secs on start; although the main blower works find, as do the rest of the controls AFAIK

While there are quite a few threads on checking/fixing the clutch gap, there is less information on a procedure for checking what that fault code might mean; the manual has the laconic "The RECIRCULATION ON and AC OFF lights will flash for approximately 20 seconds if a fault is detected in the ECC system" and recommends taking the car to a dealer.
https://www.matthewsvolvosite.com/forums ... f=1&t=3949
This thread mentions that codes may be retrievable; also that a typical problem is with the cabin air temp sensors (located where?), excessive current draw on fan (??)

Is someone willing to give some tips on where to start?

Post by **abscate** » 31 May 2015, 18:10

My AC flashes on startup, my recirc door sticks and the system faults.

The 1999 ME7 is different from the 1998 earlier in how it controls the AC.
Get that clutch gap set ( either bread clip fix or shim) and see if your AC charge is okay.
I had to replace my evaporator after 10 years. Big labour job.
These cars have great climate systems and are very comfortable.

paredown · Post by **paredown** » 01 Jun 2015, 05:34

So the flashing will not prevent the system from working? Good to know.

I'm sure that there is little/no charge in the system, so it will be clutch, then charge and I will hope that I don't have to replace the evaporator--I saw the pictures, and that looks like a nightmare!

Post by **abscate** » 01 Jun 2015, 06:28

It's stupid work, not that bad. No way is it worth paying 100+'an hour for that

You have to think carefully before diving into AC on an old car. If the system has been out of Freon for a while, it could be corroded up and get expensive.

obayha · Post by **obayha** » 01 Jun 2015, 07:01

Please post if you find anything that relates the blinking light to what might be going on in the system.
The start up of summer had me turning on my A/C only to find out the left side blows out cold air and the right side is hot air. So for now I have shut off the vents on the right side and that has helped, except the floor vent still blows heat on right side.
Most talk about the motors and or cables when the system isn't acting right. This must be pretty involved to figure it out. Also added is the fact that I have that terrible old car smell coming through the system. Musty when just the fan is on and not as bad with the A/C cooling down the stench.
I am guessing the cure would involve removing the dash to get to the evap and cleaning the fins of 16 years of moisture deposits.
Not much help, just letting you know there are more of us in the boat than you might think.
My plan is to tear into my non working '98 and see what is involved before I do the '99. Could be awhile.

paredown · Post by **paredown** » 10 Jun 2015, 15:49

Well today was the day--after getting the Volvo inspected, I thought I would continue and hope my luck would hold.

So I bought basic recharging kits at WallyWorld, and proceeded to do my Toyota Tundra first. It was fairly straight-forward--the clutch continued to cycle on and off until I got a decent charge in the system, then I topped it up, relying on the ambient temp/pressure suggestions on the can.

The Volvo was a little weirder--I put the remainder of the can from the Toyo on and the gauge showed there was a little charge in the system. I tried adding some more with the engine running, but could not hear the compressor clutch cycling. With a fair amount I was still not getting a pressure reading either.

Thinking I had a problem with the clutch I did the bread bag shim trick, and then tried adding more--pressure had dropped on restart--and I fairly quickly got very high pressure on the gauge--and no cold air, and no real compressor sounds. I thought I was going to blow the thing up...

Then I took the shims out (compressor was pretty hot and I thought maybe it was running continuously. With the shims out, I restarted, and I could hear the compressor cycling, and the gauge dropped so it was cycling from 25 to 50lbs as the compressor kicked in.

I continued to add--around the 24 oz (or a bit more) that I read was the correct amount and it stabilized at around 35 lbs of pressure. ( I forgot the trick of checking temps at the vents, but it seems pretty cold in the cabin.)

I have no idea what was going on at first--Do systems get air-locked or blocked? My secret fear of course is that I broke something because I didn't know what the heck I was doing, but I suppose all's well that ends well.

As of right now, I have A/C (although the blinking lights continue to flash at start-up) and my wife will think I'm a genius, so guess that's as good as it gets.