Air Conditioning Not Working After Being Charged

[stevestrat]

Originally Posted by SD1too

I doubt it Hector because the 1.8 cars were not fitted with the 3 speed system.

My 53 plate 1.8T had a 3 speed fan.

[JefferiesFarnol]

Originally Posted by SD1too

I doubt it Hector because the 1.8 cars were not fitted with the 3 speed system.
If you can't see a resistor visible through the radiator grille you may have the early 2 speed system without a resistor. Alternatively you may be one of the few who has the resistor mounted out of sight.

You've reported that the trinary switch test results in the high speed operating intermittently. That's a classic sign of an open circuit resistor.

To answer your question, the air conditioning can still be activated with a faulty fan but it won't cool properly. Yes, you should use 'Econ' mode until you've repaired the fan.

Your next move should be to expose the fan motor. If it has two wires entering the casing it's a resistor system and if it has three it's a non-resistor system, both 2 speed.

Simon

Thank you for your message. I didn't realise that there was another fan! I definitely can't see a resistor through the grille so I will do as you suggest and check how many wires are entering the casing. It seems I may have the 'K1.8' fan described here: https://www.mg-rover.org/threads/mg-...ration.137032/
In which case, would it still be worn brushes causing the fault or a resistor as in the later two speed fan?

[SD1too]

Originally Posted by JefferiesFarnol

... would it still be worn brushes causing the fault or a resistor as in the later two speed fan?

The original 2 speed fan had three wires (R, B, P) to the motor casing and no resistor. Loss of low speed is very likely to be the result of a worn brush in the low speed earth circuit. It cannot be a resistor because there isn't one!

The later 2 speed fan had two wires (R, B) to the motor casing plus an external resistor for the low speed. This resistor fails open circuit. The brushes last much longer due to the way they're connected.

We will have more to go on when you've removed the bumper/headlamp surround and we can see how many wires your motor has.

Simon

[JefferiesFarnol]

Originally Posted by SD1too

We will have more to go on when you've removed the bumper/headlamp surround and we can see how many wires your motor has.

Simon

Hello, Simon, firstly - thanks for all your helpful advice!

I was able to take off the grille and some of the plastic housing this evening and could definitely see three wires, red, black and purple. It was harder without the whole bumper off, I tried to get some pictures but they came out shockingly bad. You can just about see the purple one in this picture:


And when I secreted myself under the car I could see the red and black ones underneath and definitely feel that there are three.

So going by your previous message that means I've still got to change the brushes. I do rather fancy the challenge now if I'm honest!


P.s. I tried the trinary switch test again this morning as I only did it in a hurry before and I don't think my tactical paper clip was making proper contact when I said the high speed was intermittent, it actually comes on constantly with the paper clip in place.

[Pistons_and_processors]

Seems like you’ve found the fault but give your condenser a check over also.
The fins in mine had disintegrated so couldn’t cool properly. This meant the fan would come on maximum to compensate.
You can see the condenser through the grill as it’s the one attached to the fan.
👍🏻


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[suzublu]

Here's mine 😎

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[JefferiesFarnol]

Blimey, that looks like it's been through the mill a few times! I'm in luck regarding the condenser as that's the part the gas was leaking from, so the garage has just replaced it. I still wonder if there's something else up as it seems the a/c should still work to some extent without the low speed cooling fan (which it isn't) but I'll get that sorted and see if it fixes the problem.

[SD1too]

Originally Posted by JefferiesFarnol

So going by your previous message that means I've still got to change the brushes. I do rather fancy the challenge now if I'm honest!

So the next stage is to consult Arctic's excellent pictorial guide on removing the motor end cap (don't grip the casing too tightly in your vice as the composite permanent magnets are rather brittle ). You can then inspect the lengths of the brushes and decide how many you want to replace. They're attached by braided wire soldered in place.

Do not buy replacements from eBay. Order directly from Engineering Carbon Products who custom-made them from an original supplied by me. As far as I know the commutators are the same on both the 1.8 and KV6/diesel motors so don't worry that they're described as "KV6".

I'd recommend that you carry out this repair as soon as possible. Try to avoid running the motor any more as there's a risk that the worn brush will pop out of its holder and that will write-off your motor and involve considerably more expense.

Please continue to keep us informed how you're getting on.

Simon

PS I'd be interested to know how many miles your car has covered before this original fan needed repair.

[suzublu]

FYI Simon, my 22 years old, 95k miles fan is original 😎

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[SD1too]

Originally Posted by suzublu

FYI Simon, my 22 years old, 95k miles fan is original 😎

Thanks Ron. Is it a 3 wire non-resistor type? Has it ever needed repairs?

Simon