Thread: Aircon/Fan stops for a sec on full

I am not sure what vehicle you have - but this could be caused by the pressure switch for the gas.

It could be tripping on low or high pressures, low pressure usually indicates a gas shortage, high pressures is normally (if the gas charge is correct) by a blockage in the pipework/filter drier, bad air flow over the condenser, or faulty condenser fans.

However as mentioned your vehicle may not be wired that way (where the pressure switch affects the internal fan) so are many are not.

And yes a/c compressors do pull a few horses from the engine - especially when the head pressure is up above normal (250 psig +)

Check the condenser fans first to see if they/it is running, then if you have a test meter check the pressure switch.

If you let me know what vehicle I'll have a look at the wiring diagram (if I have it).

Ladas

96/Disco/tdi

Okay on the Disco TDi the internal fan is not interupted by the pressure switch. So we can count that out.

So it looks more like a loose connection, faulty switch, faulty blower relay and/or bad earth on the relay or poor earth at the motor, and as it is only on full speed we can eliminate the fan speed resistor pack - (full speed bypasses the resistor pack)

It could be a loose fuse or dirty contacts on the earth.

I have attached a copy of the wiring for that part - it's pretty basic so you shouldn't have to do much to trace the fault

Thanks for that. Looks like I have to stick my head near the fuse box and follow some cable. Sounds like fun

Matt

Mine does the same thing ,only on 4 setting , I found this only happens when engine is still cold and need cold air on myself quickly , but I'm use to having it on 3 , with no problems , 4 is just a lot of air . cheers alex

Hi Matt,

Just been through this with another one. Could be 1) fan switches on these can 'melt' slightly
2) fan speed controller can have seniors moments/ connector plug issues, or 3) there is a loom that can rub through up on the LH side behind glovebox, under the Airbag support bracket. This was the problem with the last one, the wiring had 'welded' the dash bracket periodically for quite some time, causing intermittent shorts and open circuits to the heater blower fan. Not one fuse blew!!!!! Give me a call, and I'll tell you how to get up under the dash to check it.
Incidentally, that vehicle had some similar use to yours.....

How did the MIG perform?

JC

I had a similar problem with mine.
I had a relay that was not holding the contacts open under load thus intermitantly cutting off the A/C.
The relay is located under the drivers side foot panel.
Swapped it with a working one and it fixed it. They are just a stand Hella relay. you need to reach up above the 1st rack of relays that you can easily see

Later I developed another problem with the A/C on speed 4.
I just tap the switch knob and instantly comes back on.
These switches are known to play up and I believe if you can remove it and give it's sliding contact points a light emery it might fix it.

[quote=Rovernaut]I had a similar problem with mine.
I had a relay that was not holding the contacts open under load thus intermitantly cutting off the A/C.
The relay is located under the drivers side foot panel.
Swapped it with a working one and it fixed it. They are just a stand Hella relay. you need to reach up above the 1st rack of relays that you can easily see

I had a look and ther e are 3 relays low down....2 yellow and 1 green......above that there is another yeloow one all by its self about 100mm or so, is that the one?