Starts and Stops VN

[vn_calais]

My aircon was working great till 1 hot day last summer. I was driving home from a 6 hour trip (dubbo....), when it started to play up.

The aircon turns on and off every 5-10 seconds or so. Because of this, it never completely cools the car down, and drives like crap, as when the aircon kicks in you loose power and vice versa. It sounds like the car is a bomb.

Anyway, I forgot about it as winter came. Now summer is back and problem is still there. Any ideas on what is going on?

 

[vt1538]

Do you mean the compressor cuts in & out or the fan?
The compressor has a overheat switch in it that could be tripping out due to a fault in the compressor,or even the high low pressure switch could be turning it off. If the fan in the car is not playing up, I would get a system pressure check done.

 

[vn_calais]

Update on the issue:

Whatever is turning on and off seems to be doing it every 1-2 seconds.
I had the aircon re-gassed in March 04.
I have an 89 VN calais


The fan seems to be fine, so I don't think this is the issue. You can really feel it when it cuts in and out, as it actually jolts the passengers back and forth as the revs drop/gain. Bit like putting your foot on and off the pedal continuously.

 

[vt1538]

Does the compressor cut in & out while stationary? If it does probe the connection to the compressor with a test light.If the globe flashes it means the problem is further back. If the light stays on constant it is either the compressor overheating or a fault in the clutch.

 

[vn_calais]

If the light stays on constant it is either the compressor overheating or a fault in the clutch.

Can you explain a bit more about the fault in the clutch idea? I have noticed my auto gear box tend to hold onto gears way too long when the car is cold, like when there is no fluid in the auto tranny. You are starting to worry me now that this could actually be a problem.

 

[vt1538]

The problem I mean is in the aircon electronic clutch.It has been a while since I had 1 apart & cant remember the earth set up on it. Either way if you can probe the power wire into the compressor at the connector with a test light & see if the power is constant or fluctuating that will help in finding the problem. Try this & post back.

 

[gsmrobinson]

On the passengers side of the car just in front of the firewall is a canister style thing that is either silver or black. it has a pipe that goes into the firewall and a hose that goes to the compressor. On the drivers side of it is a little pressure switch with two wires connected to it.

Remove these two wires and connect a paper clip between them. now see if the car still cuts in and out. If it does (and I doubt it will) then you need to get back to us. If it stops work out if the fluctations happen within about 20 seconds or as soon as you rev the engine or if it happens after about 2 minutes. after testing REMOVE THE CLIP otherwise you WILL stuff the compressor.

If it happens straight away or as soon as you rev the engine then it is low on gas. If it is longer then the system is over pressured because of high pressures. The last thing may be a blockage in the system, nothing you can do about this yourself.

Regards Guy