Air con compressor relay - Page 2

Jools99 · Aug 24th, 2016, 23:38

Thanks Cheshire - I did the check and there's no voltage at the connector when AC is switched on (engine running etc).
I don't have easy access to VIDA - is there a way of testing the sensor by bypassing or shorting it etc to get a definite good signal from it so I can check if that's the issue ?

ta
jools

XC70Bob · Aug 25th, 2016, 16:13

" This confuses me a bit as I would have expected if there was a leak the system would have leaked all or most of the way down – cos when I pushed the schrader down it sounded like it was more than a low pressure still in the system. "

I don't think you can use this method to test for gas in your system.
gas pressures in A/C systems are in 150 to 200psi range and the low pressure switch will cut in long before all the gas has escaped, so even if the low pressure switch has activated you might still get a good escape of gas when you tried your method of testing as I doubt you could tell the difference between gas at 50psi and 100psi
low pressure switch will normally operate when the pressure is below the 50psi mark.

Jools99 · Aug 26th, 2016, 12:43

folks -
I connected 12V to the compressor clutch (via a 5 amp fused supply) and the clutch pulled in fine (several times) – so the clutch and gap looks ok.

Per Bob’s comment about the pressure I wanted to check the pressure on the low side & do this I needed to remove the power steering reservoir to get to the connector – but I couldn’t ! The clip that retains the reservoir would not release and I didn’t want to force it without asking the forum if there’s a trick to this one - or do I simply cut thru it (or similar ?) – any advice much appreciated.
Understand Bob’s comment that the system may simply have a slow leak and is low on refrigerant – but it was regassed properly last summer (old stuff removed, evacuated for a time to check for leaks, refilled by mass) – so I’m surprised it has leaked down to a point where’s there some pressure in the system but insufficient to allow it to run – in the time since last regas I would have expected it to leak all the way down to virtually nothing ?
I have just ordered a UV torch off ebay to search for the leak – in the hope that the regas last summer used a dye in the refill.
I will report back.
Thanks for all your help
Jools

MPE · Oct 19th, 2018, 20:07

Hi, Has anyone got a working link to TP3964202 2003 v70 WIRING pdf ?

Oct 19th, 2018, 20:07	#14
MPE Junior Member Last Online: Apr 22nd, 2024 17:26 Join Date: May 2015 Location: Norfolk UK	V70 wiring diagram Hi, Has anyone got a working link to TP3964202 2003 v70 WIRING pdf ?

Aug 24th, 2016, 23:38	#11
Jools99 Junior Member Last Online: Mar 22nd, 2024 03:42 Join Date: Nov 2011 Location: Yeovil	Thanks Cheshire - I did the check and there's no voltage at the connector when AC is switched on (engine running etc). I don't have easy access to VIDA - is there a way of testing the sensor by bypassing or shorting it etc to get a definite good signal from it so I can check if that's the issue ? ta jools

Aug 25th, 2016, 16:13	#12
XC70Bob XC70 SE lux D5 Last Online: Feb 25th, 2024 14:34 Join Date: Jan 2011 Location: Mansfield, notts	" This confuses me a bit as I would have expected if there was a leak the system would have leaked all or most of the way down – cos when I pushed the schrader down it sounded like it was more than a low pressure still in the system. " I don't think you can use this method to test for gas in your system. gas pressures in A/C systems are in 150 to 200psi range and the low pressure switch will cut in long before all the gas has escaped, so even if the low pressure switch has activated you might still get a good escape of gas when you tried your method of testing as I doubt you could tell the difference between gas at 50psi and 100psi low pressure switch will normally operate when the pressure is below the 50psi mark.

Aug 26th, 2016, 12:43	#13
Jools99 Junior Member Last Online: Mar 22nd, 2024 03:42 Join Date: Nov 2011 Location: Yeovil	folks - I connected 12V to the compressor clutch (via a 5 amp fused supply) and the clutch pulled in fine (several times) – so the clutch and gap looks ok. Per Bob’s comment about the pressure I wanted to check the pressure on the low side & do this I needed to remove the power steering reservoir to get to the connector – but I couldn’t ! The clip that retains the reservoir would not release and I didn’t want to force it without asking the forum if there’s a trick to this one - or do I simply cut thru it (or similar ?) – any advice much appreciated. Understand Bob’s comment that the system may simply have a slow leak and is low on refrigerant – but it was regassed properly last summer (old stuff removed, evacuated for a time to check for leaks, refilled by mass) – so I’m surprised it has leaked down to a point where’s there some pressure in the system but insufficient to allow it to run – in the time since last regas I would have expected it to leak all the way down to virtually nothing ? I have just ordered a UV torch off ebay to search for the leak – in the hope that the regas last summer used a dye in the refill. I will report back. Thanks for all your help Jools

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