AC not getting cold (contactor wiring)

[Sladey]

It’s as the title says really.Since I’ve got the car running again the weather has been rubbish so initially I put it down to it not being warm enough, but on a trip on Sunday it was quite stuffy in the car and we had the blue button on and off (with blowers blowing) and couldn’t feel any difference in the air coming out of the vents. The day before I’d changed the target temperature from 30 degrees to 18 in the hope that I would notice a difference

Last weekend I tested the battery and at 900rpm tick over I’m getting 14.5V at the battery.

Tonight I’ve logged into the ECU and tried to start the compressor. I’ve got the engine running. I can’t feel if it’s running or not - I’m feeling vibration through it but I’m also feeling that through the battery - general vibration of the car running. I tried CMP=1 and CMP=0 - both times got OK message but no change in how it feels 

I’ve uploaded the RUN output and also more detailed DIAG output, as well as a LIST output

I did try changing SIG from 0 to 3 after reading another post on here (I’m not sure what compressor I have) but it didn’t change anything

 

Any ideas?\

 

Sladey

 

 

[classicretrofit]

Hi Mark, have asked Jonny to take a look at your screens.

[Jonny Retrofit]

From your trace, the system is ‘Off’.    What is your blue button doing?   It should illuminate bright when pressed.   If it doesn’t, check the button wiring.  Do you have 12V and GND to the button harness?

 

 

[Sladey]

The button seems to be reacting as normal - with the fan running the button was bright blue. 
 

[Jonny Retrofit]

Ok, please post a trace in DIAG capturing the startup.   It should say ‘Hi Power’.

[Jonny Retrofit]

Do you hear the contactor click?

[Sladey]

Ok I’m away at the moment but will try tonight and post results. 
 

I didn’t hear the contractor click at all

[Jonny Retrofit]

Ok, you should have a grey wire and a ground on the contactor.   There are two M8 ring terminals on the loom that need a good ground.

[Sladey]

OK so I’ve had a go tonight:_

Startup - engine idling, fan on, pc not connected

Dim blue light

Switched fan off - no change in blue light 

 

I connected up the PC - I’ve had real trouble with the connector - the USB connection isn’t very good and it can take a few goes until it connects properly and then I have to be careful not to move the laptop

With the fan on I pushed the button - got bright blue light 

First pic - here is what was 

 

then I typed diag and got the following output (pic 2)

 

 

I then tried switching off the engine (not turning the ignition all the way off) then restarted it ( it stalled first time) and got this (pic 3)

 

 

Then I tried diag again and got this (pic 4)

 

I tried CMP=50, CMO=0 - no change. I tried CON=1, CON=0 - no change - couldn’t hear the contractor but it’s hard to hear anything with my engine ticking over - I don’t know if that works without the engine running

Edited June 20, 2024 by Sladey

[Sladey]

OK just to add to this I haven’t connected a contactor relay - the instructions say this is optional and I didn’t think I’d be needing it

[Jonny Retrofit]

The ECU is doing the right thing ( sending duty and enable ) but the compressor is not starting (current is 0).  This usually happens if the compressor doesn't have a decent connection of the red cables and ground.  

Have you made any changes to any of the kit supplied, e.g. the power cables or the fuse provided?

[Jonny Retrofit]

9 hours ago, Sladey said:

OK just to add to this I haven’t connected a contactor relay - the instructions say this is optional and I didn’t think I’d be needing it

I see the contactor in your pictures on DDK... 

[Sladey]

Thanks for coming back to me. I'm at work now so I'll have to revisit it tomorrow.

I'll re-check the wiring in the morning. I haven't intentionally changed any of the wiring. 

Regarding the contactor relay - I'm misremembering this - there is an option to wire something in to stop the compressor if you choose to have heated seats for example. That seemed like added complexity to me and I didn't understand the instructions so I decided not to do that. 

 

[Jonny Retrofit]

True - you don't need the 'defeat' wires if you have the hi power alternator.

Your contactor should definitely click when the system is switched on or when you issue a CON=1 or CMP=50 test command.

[Sladey]

IT LIVES!!!!!!

yes I hadn’t got those two thin wires connected to the contactor.
 

In my defense on the wiring diagram there are two bits that it says are optional - one is the defeat thing and the other is on the connector. I assumed these were part of the same “optional” defeat thing and therefore taped those two leads off. 

Also the way I’ve mounted my contactor the two connection spades were all but invisible so looking at the setup there was nothing obviously unconnected

all good now and looking forward to driving in the coming nice weather

thanks for your help

[Jonny Retrofit]

Good to know!  Enjoy!