Archived Message
Aircon not blowing
Heater motor blowing on heat or cold,but when you put aircon on it kicks in but nothing comes out of the vents and the heater motor is still switched on. Can anybody help?
Brian Higginson
23/05/2012 @  12:20
Under topic: RV8
Archived Reply(ies) received for this Message
Aircon not blowing
As I recently had to aquaint myself thoroughly with the RV8 aircon system:

There is a changeover relay that switches between the heater fan and the AC blower fan. If that relay would fail then you would get those symptoms. Is the other A/C stuff working (condenser fans at the front for example)?
Erik Persson
23/05/2012 @  23:40
Aircon not blowing
Yes everthing is working, just not blowing, thanks for the tip, where would I find the relay?
Brian Higginson
24/05/2012 @  13:47
Aircon not blowing
I think you will find the 3 relays in the engine compartment rear left. As you look at them, it is the left hand one which controls the blower motor changeover. The centre one is for the compressor clutch and the right one for the condensor fans.
Peter Garton
25/05/2012 @  16:05
Aircon not blowing
Aircon changeover relay OK, any ideas?
Brian Higginson
29/05/2012 @  11:09
Aircon not blowing
That is indeed a bit confusing. I re-checked the wiring diagram and the fan circuit is actually only dependent on the AC switch and the changeover relay, meaning that the AC fan would engage regardless of wether the rest of the AC system is working.

If indeed the other parts of the AC switch kick but the heater fan stays on then the switch obviously works and the fault must be with the relay or the wiring from the switch to the relay.

Some perhaps a bit basic questions:

Has the system ever worked in your car? When engaging the system there should be an audible "clunk" from the vacuum solenoid shifting the centre vent feed to the other fan, the two condenser fans at the front will howl to life and a metallic "click" a brief moment later will announce that the compressor clutch engages. The clutch will only engage with the engine running and if the thermostat in the evaporator (under the dash) doesn't think it's too cold.

Are you certain that the heater fan is blowing - i.e. is there blowing air from the defroster and the floor vents? Could you be confusing the noise from the condenser fans with the heater fan noise?

And just to make sure: Are the centre vents open?

Best regards,

Erik Persson
30/05/2012 @  07:39
Aircon not blowing
If you are really stuck, Brian, rather than try to do it all by yourself why not take it to a Bosch or equivalent service outlet and let them test the unit to see where the problem lies. This can't cost the world and they would be able to tell you the cause of your dilemma via a relatively short testing procedure. As Erik has stated, there are several areas which can cause you trouble and so, one has to go at it systematically and also possess fairly good electrical knowledge. It is not clear to me whether you compressor is kicking in via a fairly loud clicking noise. When you press the cooling switch on the dash rhs there is a terrible crude noise of the fans working at the front of your engine. If you don't get this loud noise, then the unit is not functioning.
For what it's worth, I get my airconditioning checked and if necessary topped up via Bosch every year. I do hope you succeed it getting it going again.
Peter Garton
30/05/2012 @  14:46
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