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gene, RV Mechanic
Category: RV
Satisfied Customers: 1100
Experience:  28 yrs exp in the industry
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Any good on chevy trucks a/c system and etx sensor /cooling

Customer Question

hey any good on chevy trucks a/c system and etx sensor /cooling fans on 8.1 vortec tks
JA: Has the A/C relay been checked?
Customer: yes and fuse and bought a new ect for the fans run all the time the engine is running
JA: What is the model/year of your Pontiac?
Customer: chevy motor 2002
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: replaced the etc/ realys ok the pins on the pcm are ok lookde at all the wiring I could see also I have a scan tool with live data which on this truck only works when the key is turned on not running I lose the connection I pulled off the conector for the low pressuer switch(hard to get to) and after three days of looking why the cooling fans allways run today it stopped with conector disconnected tks
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 11 months ago.
Category: RV
Expert:  Chris (aka-Moose) replied 11 months ago.

Welcome, I'm Chris (aka Moose), my normal schedule online is around lunch and after dinner past midnight.

  • Sorry no one has helped yet.
  • I can help with this question.
  • Reply and let me know when your able to work on this concern.
Customer: replied 11 months ago.
Hey Moose Hello lets go and fix this beast chevy 8.1 Votrec.. the electric cooling fans run all the time the engine is running. I checked the relays and switched them and no difference also the a/c and defrost is turned off even with the a/c relay pulled the fans run..looked at the wiring about 80 % and the pins on the connectors of the pcm ok..I did find something if I pull the connector for the low pressure switch the fans stop running...I ran the engine till it was 228 degrees according to the scan tool then the fans kicked in and stopped at about 195 degrees Now the scan tool that works on other cars a Innova 3130 with live data will not read live data with the engine running.. I have to turn on the ingition and hit the ld for readings Now the a/c was charged about two months ago ans works fine any ideas what to look at thanksso much Norm(nitro)
Customer: replied 11 months ago.
Hello again do u think it may be something is the a/c controls telling the pcm to ground out the fan aux relay tks nitro
Customer: replied 11 months ago.
Hello another update I pulled the connector for the dash selector control out of the selector switch and ran the engine at the low pressure switch plug pulled also wires black ( to ground) and a light blue live 11.3 volts to ground pulled the relays for fan and a/c still have power at the light blue wire that must come from the pcm?? hot all the time...what would u suggest next Nitro
Expert:  Chris (aka-Moose) replied 11 months ago.

Can I get the vin# ***** I am looking at the correct diagrams?

Customer: replied 11 months ago.
of course now I said chevy engine so it will not be that complicated when it is a 2002 Winnebago motor home on a workhorse w22 platform vin last 8 is 23349548 and also engine running all relays in place dash control off pull the low pressure switch, 30 seconds later the cooling fans stop thanks so much for your help nitro
Expert:  Chris (aka-Moose) replied 11 months ago.

Sorry I do not work on the RV chassis. I will opt out.

Customer: replied 11 months ago.
I'm sorry to hear that the area we are talking is GM from builders of the Workhorse platform The pcm, a/c compressor high pres switch low pressure switch condensor and all related components are all GM. Same as in any chevy truck or GMC truck the The only difference is the control and the blower fan for heat and a/c that was made by the coach builder I as sorry to see u go nitro
Customer: replied 11 months ago.
May I ask a question regarding info I found out on the internet?? I have no codes showing with my scan tool but will the scan tool at the GM dealership show hidden codes like A/C high pressure that will keep the cooling fan running till the code is cleared at the pcm thanks Norm just a thought
Customer: replied 11 months ago.
I have made a statement here did u get it??
Customer: replied 11 months ago.
This engine is from GM and the low pressure switch disconnected the fans stop after 10 seconds
Customer: replied 11 months ago.
With the low pressure switch the fan operation is as required by GM starts when 228 degress and stops when 195 degress do you think there is too much pressure at one time in the a/c unit and the pcm has a code that is retained and runs the fans as I cont remove the code with my scan tool thanks Norm