Climate Control Issues - Cabin Temperature Sensor? Gas?

[sifaan]

(I'm back after a long silence!)

 

The car (2001, 2.0i) has been having trouble with it's AC on and off. Most recently it was that the heater blower resistor kept blowing and was advised to change the blower motor (if the contacts wear down, it could be pulling more current and causing the resistor to overheat) so I did that and that seems to have solved that part of the problem

 

When the outside is cold (by SriLankan standards; 24-26 C) the AC works fine even for driving more than 1 hour. It is only rarely that it doesn't work

 

When it is hot outside, the A/C works for a while, then stops working (blower is active, but not cooling) then starts again, stops again, etc.

sometimes it even blows hot air

 

The car has some wiring issues (harness was damaged by fire and has been patched up) and this can sometimes give spurious error messages - but if this were the cause of the AC problem I'd expect that it should be the same regardless of the outside temperature. (unless the wires themselves heating up is causing a contact issue)

 

Could it be that the cabin temperature sensor is malfunctioning? I can't find such a thing in the parts diagram but climate control can't work without at least 1 cabin temperature sensor, right?

 

Or could it be that there's not enough gas, hence the compressor cuts out when it gets overworked? in sri lanka they don't top up gas by weight (625g i think is the recommended amount) but rather keep putting gas until the temperature at the vent reaches a particular value (I think 4 C).

 

Or could it even be that there's too much gas?

 

Thanks

/Sifaan

[Johndouglas]

That sounds similar to my previous C5 in that the aircon just didn't seem to be working all that well.    I got a mobile guy to do both the C5 and the Xsara.   First he checked them for leakage and when that was ok, he recharged them.   Afterwards both were on the top line.

[paul.h]

Welcome back Sifaan.

 

Did you manage to sort your air bag fault ? We had somebody a few weeks ago with something similar and I linked a reply to your posts but without knowing the outcome we could not really help.

 

Air con problems on our C5s have been not cooling enough due to low gas after about 7 years with one side of the vents being a bit warmer than the other. As John says, here the old gas is removed and weighed, a leak test is done and then gas is put back to the correct weight. With enough gas the air con should cool to about 4°C out of the central vents, but if your outside air temp is very high then maybe it may not get that low.

 

If your car is overheating the air con is automatically cut. The compressor will also have low and high pressure switches that stop it - low gas pressure being a sign of low gas and high pressure a sign the condenser (front radiator) is not removing enough heat to condense it. So you can check if the condenser is blocked externally or the fan is not running enough. The heat removal rate will depend on the air flow and outside temperature - the lower the temp then more heat can be removed. If the air con works at a low cabin fan rate but not high, this may indicate the condenser is limiting.