High side fan not kicking in

[joeyt1144]

I recently had the ac compressor and everything replaced and got the car home and worked fine for about a week. Then all of a sudden the AC stopped working so I took it back tot he shop. They checked and said the hi side fan wasn't kicking in properly and said it was most likely electrical. Any suggestions?

Joe

[XJSman89]

The most obvious thing to check would be fuses and relays, but beyond that I wouldn't know what to do. Someone will know!

[sall]

High side fan, eh? Does he mean the AC high side pressure switch by chance?

Can you describe what happens a bit better? When AC is 'on' does the compressor engage at all, does it make noise, etc?

[tigger]

Oct 1, 2014 23:41:24 GMT -6 joeyt1144 said:

They checked and said the hi side fan wasn't kicking in properly and said it was most likely electrical. Any suggestions?

No offense intended, find a new shop.

[joeyt1144]

Ok I got new compressor and when the ac is on for a while the compressor stops. The ac man said that it was likely something electrical with the high side fan?? I think that is what he said. Told me if I don't get it fixed ac would eventually burn up

[oldsAURORAmobile]

On our cars, there is no high side fan. Both fans operate together at high or low speed depending on temperature.

As a matter of how it functions, the compressor cycles on and off based on pressure.

Do you mean it stops blowing cold air? If it doesn't come on at all, one of the pressure switches or connectors could be bad. Maybe he told you high side switch?

[joeyt1144]

Maybe I need new high side switch. I have till the summer to figure out. Now have to find out why air doesn't blow with force. Also the heater isn't as hot as it should be.

[genedjr]

I just fixed the AC on the 01 this summer.  And unfortunately I knew nothing about how an AC works so this took me about 100 hours over 2 months to figure out and fix.  But now I know quite a bit about how an AC system works.  Particularly on the Aurora .  BTW - I am not sure if the first gen's use R12 or 123a.  If yours used R12, the shop should have converted it to 123a.

There is no high side fan - as someone else suggested, get a new shop. 

The AC system system has a high pressure side (from compressor through the condenser in front of the radiator to a orifice tube.  And a low pressure side from the orifice tube through the dryer to the evaporator back to the compressor.  The high pressure side condenses the 123a coolant back to a liquid which creates heat and the low pressure side uses the evaporator (under the dash) to expand the coolant making it cold. The pressure is controlled by the orifice tube.  There's more to it, but I hope that is enough to get the idea.

Note that the low pressure side and high pressure side ports are on each side of this orifice tube.  These should have screw off caps on both, mine are black.  (on the Acura one is red (high) the other blue (low).   The low pressure side is the one closer to the firewall and where you would add 123a coolant.  Don't worry, the store bought 123a filler hoses will not fit on the high pressure side.

The compressor will disengage when the sensor at the evaporator is cold enough. This is supposed to keep it from freezing. So check it a couple of times after it has sat and (oddly) warmed up. I bet it starts.

Here are a couple of other ideas -

Blend door actuator (left and right are blowing with different temps/force but should be the same) or the mode door actuator (same actuator part I think, but different location) when not enough force or its stuck on vent, or floor or defrost.

If the pressure is not high enough once the compressor starts, it will shut down to keep from burning up.  But this happens almost immediately.  With the engine running and the ambient temp above 60 degrees, if you have someone turn the AC on while you watch the compressor and it kicks in then stops in a couple of seconds, it probably has a coolant leak.  If it does not kick in at all and you know there is enough coolant in there, it might be the high pressure switch.  This is located very close to the compressor on the high pressure side AC hose.  Check the connection.  I had a good switch but so much goo from the leaking valve cover gaskets had contaminated the connection.  Once cleaned it worked as expected.


If you are the adventurous type, you can get a set of 123a AC gauges from Harbor Freight for under $50 with coupon.  Once the compressor has been running for about 30 seconds you should see about 30lbs on the low side and about 130-150lbs on the high side.  And you should see fluctuation as the compressor is cycled on and off.  There are alot of videos showing how to use the gauges.

If you paid these guys to fix it and it did not stay fixed and now they want more money - go somewhere else.

Give us more detailed description of what you see and feel with the AC and I am sure the brain trust here can help.
...gene

[genedjr]

Nov 8, 2014 22:36:09 GMT -6 joeyt1144 said:

Maybe I need new high side switch. I have till the summer to figure out. Now have to find out why air doesn't blow with force. Also the heater isn't as hot as it should be.

If you hear the fan running at high speed, but do not feel the enough force is being produced, it is either a blend/mode door broken, or more likely the actuators. 




GM used these pesky things all over the place in many makes and models as far back at 1990 (maybe farther, but I see one in my PU )  And the Aurora is no exception, its a lots of them.




These little beauties have plastic internal gears and as they age get brittle and break.  So working perfectly one moment, not working the next.
...gene