P38A EAS Compressor thermal switch: Sorted. Switch is kaput.

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MacMan6107

MacMan6107

Well-Known Member
Posts
196
Location
Somewhere in Scotland.
Hi folks,
Would anyone happen to know why after having installed a new air compressor, but filled up the airbags with a workshop air compressor, then when performing all diagnostic checks in the vehicle and after testing the compressor (using Hawkeye) it is saying the Thermal Switch is hot? Up to that stage, the longest I had allowed the compressor to run was no more than 10 seconds.
When I received the compressor the first thing I did was test it out of the vehicle applying 12v to it and it worked.
I have searched all morning and can't find any information on this at all. Should the compressor be doing this?
Also while running the vehicle I wasn't able to raise or lower the vehicle via the dash buttons. Could that be because of the air compressor?

Thanks in advance

Craig
 
MacMan6107 said:
Hi folks,
Would anyone happen to know why after having installed a new air compressor, but filled up the airbags with a workshop air compressor, then when performing all diagnostic checks in the vehicle and after testing the compressor (using Hawkeye) it is saying the Thermal Switch is hot? Up to that stage, the longest I had allowed the compressor to run was no more than 10 seconds.
When I received the compressor the first thing I did was test it out of the vehicle applying 12v to it and it worked.
I have searched all morning and can't find any information on this at all. Should the compressor be doing this?
Also while running the vehicle I wasn't able to raise or lower the vehicle via the dash buttons. Could that be because of the air compressor?

Thanks in advance

Craig
Click to expand...
Have you cleared all faults and reset the EAS system?
I always find the late great Wammers guide to EAS in tech archive very helpful
 
CHECKING THERMAL SWITCH ON COMPRESSOR THAT DOES NOT RUN ON VEHICLE.

Remove compressor plug from socket. Test continuity between Orange wire and Black wire. If continuity switch is ok. If none switch is duff. OR if you don't own a test meter. Leave plug connected and strip a small amount of cover on Orange wire back. Connect a wire to this and run it to ground. If compressor then runs thermal switch is duff.


I did as the above says on the new compressor and the one being replaced. From orange to black on both nothing happened. Yet when I did green to black the multimeter beeped and the reading is 0.6/0.8, on both.
 
MacMan6107 said:
CHECKING THERMAL SWITCH ON COMPRESSOR THAT DOES NOT RUN ON VEHICLE.

Remove compressor plug from socket. Test continuity between Orange wire and Black wire. If continuity switch is ok. If none switch is duff. OR if you don't own a test meter. Leave plug connected and strip a small amount of cover on Orange wire back. Connect a wire to this and run it to ground. If compressor then runs thermal switch is duff.


I did as the above says on the new compressor and the one being replaced. From orange to black on both nothing happened. Yet when I did green to black the multimeter beeped and the reading is 0.6/0.8, on both.
Click to expand...
Thermal switch is no good then. Thats your problem
 
MacMan6107 said:
In a brand new OEM compressor?
Click to expand...

Sounds odd but maybe someone hamded it back having fried it? Was that with it unplugged? If the other wires touch with power applied then it will fry the switch. It can be replaced but why bother when you have a duff unit? I guess the only other option is that a wire has chafed somewhere and shorted, frying the switch.
 
Grrrrrr said:
Sounds odd but maybe someone hamded it back having fried it? Was that with it unplugged? If the other wires touch with power applied then it will fry the switch. It can be replaced but why bother when you have a duff unit? I guess the only other option is that a wire has chafed somewhere and shorted, frying the switch.
Click to expand...

Yep, I tested the compressor while it was unplugged from the wiring harness. All I can think of is when I received the delivery of the item the packaging appeared to have been torn open, it was a whole corner ripped apart. It is possible that the compressor may have fallen out of this hole and damaged the internals somehow although I don't know how. There are no signs of external damage to the compressor so I have nothing to go on really. When I received the box I did take photographs of the damage to the box and emailed those photos to the vendor after having spoken to them on the phone that same morning.
They later in a reply email accepted liability for the compressor not having been packed correctly and instead allowing it to move freely within the box. The person who replied to my email ensured this would not have happened had they had packed the item and instead threw a fellow employee under the bus blaming them. At the time they were aware I was not immediately installing the compressor to the vehicle and would be doing so after ensuring everything else was as per spec before I did install it and that this would take at least a week or slightly more.
So I have emailed them again stating the tests etc. that I had performed and shall now wait to see if or how they are going to respond to this.

Thanks for your help gentlemen.

Regards

Craig
 
MacMan6107 said:
Yep, I tested the compressor while it was unplugged from the wiring harness. All I can think of is when I received the delivery of the item the packaging appeared to have been torn open, it was a whole corner ripped apart. It is possible that the compressor may have fallen out of this hole and damaged the internals somehow although I don't know how. There are no signs of external damage to the compressor so I have nothing to go on really. When I received the box I did take photographs of the damage to the box and emailed those photos to the vendor after having spoken to them on the phone that same morning.
They later in a reply email accepted liability for the compressor not having been packed correctly and instead allowing it to move freely within the box. The person who replied to my email ensured this would not have happened had they had packed the item and instead threw a fellow employee under the bus blaming them. At the time they were aware I was not immediately installing the compressor to the vehicle and would be doing so after ensuring everything else was as per spec before I did install it and that this would take at least a week or slightly more.
So I have emailed them again stating the tests etc. that I had performed and shall now wait to see if or how they are going to respond to this.

Thanks for your help gentlemen.

Regards

Craig
Click to expand...
When you tested it which wires did you put your live and neutral to, as you don't involve the thermal switch when bench testing
 
MacMan6107 said:
As per the technical archive and what it states there to do for testing the compressor.
Click to expand...
Your thermal switch was duff. On the bench you put live and neutral direct to motor hence seeing it run. The orange wire is a signal from EAS to relay for the compressor to run. So duff switch compressor don't run as no signal. Easiest way to explain
 
marjon said:
Have you still got your old compressor?
Test the thermal see if its good, if you get a bad response from the seller then maybe just change them over;):).
Oh and shame the seller:D.

J
Click to expand...
About £10 for a compressor refurb kit. Could be worth doing that as well. When I changed my compressor I refurbished it and now got a spare
 
marjon said:
Have you still got your old compressor?
Test the thermal see if its good, if you get a bad response from the seller then maybe just change them over;):).
Oh and shame the seller:D.

J
Click to expand...


Hahaha I do but it is also done and dusted as well. This is the 6th compressor in the car that I am aware of. Which is why I didn't install it straight away. I wanted to see if there was something causing the issue but all tests I did came back as if there was no issue except for the compressors. Earlier ones could have been because the car was on its original bags and I changed them back in 2019 which is when the compressor literally seized up the first time. Then I bought a new compressor and after 3 months it died so I contacted the seller who sent me out a replacement that worked fine until a few weeks back.
I had a look at the guts of the electrics in the 2 dead pumps I had to see what was involved with regards to replacing the switch but I seriously don't understand how electwizardry works. My dad was an electrical engineer and always relied on him. Yep he tried teaching me but it wouldn't ever stay in my head. Anyway he is gone now and that's all off point.
The seller of this latest compressor has replied and are going to pay for return shipping and will send out a known working compresser. So here's hoping that gets the car back on the road for a few days before I take it off again to fix a coolant leak.
I tell ya what. In Australia we could fix our cars all year round pretty much and actually get some good hot months running with them. Over here with this one, I seem to spend all summer out working on it chasing issues that keep popping up. Know what though, I love it really hahaha
 
Rubberknees said:
About £10 for a compressor refurb kit. Could be worth doing that as well. When I changed my compressor I refurbished it and now got a spare
Click to expand...

Refurb kit dont include the thermal switch though, so he wouldn't be left with a "plug & play " spare;)
But he may be just aswell off refurbing what he has, and battle the seller:D

Just trying to think of maybe quickest way to get up and running:)

J
 
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