AC pump not pumping - 2010 Aygo

[gullarm]

Last week I replaced the alternator/belt and water pump. The alternator had jammed solid so decided to replace all the items at the same time. I haven’t been driving it since last march but have been running it every couple of weeks.

The car has always made a weird squealing noise after being left for 2-3 weeks and I finally found out it was the alternator that was sticking but somehow freeing itself, but it finally jammed solid.

Now after getting it all back together the a/c pump isn’t working.

There is no power gong to the cable that connects to the A/C pump to engage the magnetic engager thing.

The A/CLight comes on and the fan is running.

I have tested all the fuses – including the one at the back of the dash. I had to remove the speedo.

 

Any tips on what it could be?

I can’t take it the garage – its SORN, UNTAXED, NO MOT and NOT INSURED.

[Aygo_Tom]

16 minutes ago, gullarm said:

Last week I replaced the alternator/belt and water pump. The alternator had jammed solid so decided to replace all the items at the same time. I haven’t been driving it since last march but have been running it every couple of weeks.

The car has always made a weird squealing noise after being left for 2-3 weeks and I finally found out it was the alternator that was sticking but somehow freeing itself, but it finally jammed solid.

Now after getting it all back together the a/c pump isn’t working.

There is no power gong to the cable that connects to the A/C pump to engage the magnetic engager thing.

The A/CLight comes on and the fan is running.

I have tested all the fuses – including the one at the back of the dash. I had to remove the speedo.

 

Any tips on what it could be?

I can’t take it the garage – its SORN, UNTAXED, NO MOT and NOT INSURED.

Hi there,

If the green light illuminates, the engine speeds up and the cooling fan operates but there is no power going to the compressor then I would check this relay, it is the A/C mag clutch relay:

 

[gullarm]

Any tips on testing it, I tried to push it in to make sure it was seated ok and to also remove it but it seems kinds stuck?

Is there a tip to getting it out.

11 minutes ago, Aygo_Tom said:

Hi there,

If the green light illuminates, the engine speeds up and the cooling fan operates but there is no power going to the compressor then I would check this relay, it is the A/C mag clutch relay:

 

 

[Aygo_Tom]

8 minutes ago, gullarm said:

Any tips on testing it, I tried to push it in to make sure it was seated ok and to also remove it but it seems kinds stuck?

Is there a tip to getting it out.

 

You should hear it click when the A/C is switched on, but even then it might not be working properly.

Here is the toyota workshop manual test for it (I had to pay for access a little while ago, for a similar issue, but mine is the clutch coil blowing the 7.5A fuse behind speedo):

As for getting it out, it should pull out but is probably seized in there.

 

[gullarm]

14 minutes ago, Aygo_Tom said:

You should hear it click when the A/C is switched on, but even then it might not be working properly.

Here is the toyota workshop manual test for it (I had to pay for access a little while ago, for a similar issue, but mine is the clutch coil blowing the 7.5A fuse behind speedo):

As for getting it out, it should pull out but is probably seized in there.

 

Cheers - ill try and yank it out after seeing if it clicks or not

[gullarm]

18 hours ago, gullarm said:

Cheers - ill try and yank it out after seeing if it clicks or not

The relay is working fine.

Removed from the car – clicks when power is applied and the terminal are working with my OHM setting DVM.

 

Checking the fuse box with the relay removed there is power to the Positive terminal of the relay when the AC switch is turned on inside the care – in fact it goes live when the blower heater is turned on but not the AC switch.

However the Negative terminal doesn’t connect to earth – so it must go to another relay/fuse/switch…… basically some were else which grounds the relay and makes the relay activate and the AC kick in.

If I short out pins 1 & 2 with a piece of wire and put the relay back in the AC kicks in. So the wiring from the fuse box to the AC is fine.

 

So what stopping it from starting normally.

How do I check there is actual AC fluid and how do I check the pressure switch on the metal pipes?

[Mooly]

I was going to suggest low refrigerant as a possible cause, particularly as you mention not using it much. I also wonder if the 'seized' alternator was actually the alternator being very hard to turn due a low state of Battery charge (high current draw from the alternator makes it much harder to physically turn).

You need proper manifold gauges to check pressures in the A/C system. 

[Aygo_Tom]

15 hours ago, gullarm said:

The relay is working fine.

Removed from the car – clicks when power is applied and the terminal are working with my OHM setting DVM.

 

Checking the fuse box with the relay removed there is power to the Positive terminal of the relay when the AC switch is turned on inside the care – in fact it goes live when the blower heater is turned on but not the AC switch.

However the Negative terminal doesn’t connect to earth – so it must go to another relay/fuse/switch…… basically some were else which grounds the relay and makes the relay activate and the AC kick in.

If I short out pins 1 & 2 with a piece of wire and put the relay back in the AC kicks in. So the wiring from the fuse box to the AC is fine.

 

So what stopping it from starting normally.

How do I check there is actual AC fluid and how do I check the pressure switch on the metal pipes?

Interestering! I didn't think that the engine would speed up/engine cooling fan would run if the pressure switch was faulty or there was low refrigerant. You could disconnect the pressure switch and see if the engine still speeds up and the fan runs when you switch AC on.

If it does, then you could short the two pins on the connector for the pressure switch and see if the mag clutch engages.

[gullarm]

8 hours ago, Aygo_Tom said:

Interestering! I didn't think that the engine would speed up/engine cooling fan would run if the pressure switch was faulty or there was low refrigerant. You could disconnect the pressure switch and see if the engine still speeds up and the fan runs when you switch AC on.

If it does, then you could short the two pins on the connector for the pressure switch and see if the mag clutch engages.

Im beginning to think its low refrigerant. I can make the pump work by by passing the relay but the AC doesn't appear to get cold ( but then its pretty cold outside anyway ).

 

Im going to try shorting out the pins on the pressure at the weekend.

It hasnt moved for 12 months so maybe lack of use has affected it - I did try and start it every 2-3 weeks.

[flash22]

Low refrigerant will stop the pump kicking in, tbh it needs a vacuum test and refill, do not run the pump with low or no fill, it will kill the pump as it's not lubricated

[Stivino]

14 minutes ago, flash22 said:

Low refrigerant will stop the pump kicking in, tbh it needs a vacuum test and refill, do not run the pump with low or no fill, it will kill the pump as it's not lubricated

Read your post back to yourself. 😀

[Stivino]

It might just need a top up.

I used to have to give my old Meriva a little gas every year or so.

[flash22]

6 minutes ago, Stivino said:

Read your post back to yourself. 😀

The OP said they were going to short the switch..............................

What will kick the pump on

[Stivino]

I realise that now that I have looked back over the thread, silly me.  At first glance I read it won't work with low gas and then if you use it with low gas it will damage the pump.

I didn't see that he was shorting out the switch.  But shorting it out only to test the system is worthwhile.

[Mooly]

If you want a quick and dirty test of whether there is at least some pressure in the system then just blip the 'low side' service port valve (it is a bit like a tyre valve). Do this with the engine OFF.

Be aware that any refrigerant can and will cause freezer burns if you are not careful. Use a blunt plastic instrument to keep fingers away from the cold. You only need blip it for a fraction of a second like giving a quick squirt of an aerosol can.

It will tell you if there is at least some refrigerant present. If nothing at all comes out then you have lost all refrigerant and possibly have a leak rather than just natural leakage.

[Aygo_Tom]

2 hours ago, gullarm said:

Im beginning to think its low refrigerant. I can make the pump work by by passing the relay but the AC doesn't appear to get cold ( but then its pretty cold outside anyway ).

 

Im going to try shorting out the pins on the pressure at the weekend.

It hasnt moved for 12 months so maybe lack of use has affected it - I did try and start it every 2-3 weeks.

The thing is, I don't think it's the refrigerant level or the pressure switch because your cooling fan runs and your engine speeds up when you turn on the AC. If you simulate low refrigerant level by disconnecting the pressure switch connector, you'll find that the engine cooling fan does not run and the engine speed stays the same when you turn on the AC. The green light will light up in both cases.

[troyvespa]

I have same problem with my Aygo 1.0 model year 2007. The gas pressure is OK, but the voltage arriving to relé is 10.8V and so not working. Any idea? 

[flash22]

 Are you checking the voltage at the relay or at the connector ? What's the voltage at the 7.5 amp A/C fuse

are you using a body ground for testing ?