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Ask Andy Your Own Question
Andy, Truck Diagnostic Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 1650
Experience:  International and Isuzu trucks , International, Maxxforce, Cummins and Isuzu engines, Diagnostic and electrical troubleshooting specialist , Hvac and truck /trailer refrigeration troubleshooter
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I have a 3406e cat and why doesn't the AC gh pressure switch

Customer Question

I have a 3406e cat and why doesn't the AC high pressure switch turn on the engine fan ?
JA: We'll do all we can to help. Tell me a bit more about what's going on so the Heavy Equipment Mechanic can help you best.
Customer: Fan kicks on good manually and when truck heats up to 210 , but when the AC is going on idle the fan doesn't kick on but the computer tells us the fan is engaged but it's not going !
JA: Is there anything else the Heavy Equipment Mechanic should be aware of?
Customer: Well when the AC is on at idle it will run good for about 3 minutes then when u watch the pressure gauges the high pressure will go up to 350 and cut it out come back down in a second cut it in for a second and does that back and forth. And when fan is on manual it doesn't do that . New compressed . The old one blew the piston out !
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Heavy Equipment Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 1 year ago.

Hi my name is ***** ***** be glad to try to help. Check the harness between the Switches and ECM as well as try swapping relays with a known good one and be sure all your fuses test good. If all checks out okay then verify the harness has not damaged wiring or connector pins causing a loss of signal from the ECM. Verify you have signal to command the fan on at the ECM plug. What is the year make and model truck as well as the prefix for your engine serial number? Let me know

Expert:  Daniel Wilson replied 1 year ago.

It is possible a software issue if the rest of the circuit check out okay.

Customer: replied 1 year ago.
I don't think is has ever worked on that truck ever since we got it , maybe u could send me a diagram on how to Conect the engine fan to the high pressure switch !
Expert:  Daniel Wilson replied 1 year ago.

What is the year make and model of your truck?

Customer: replied 1 year ago.
What a ripoff that was !
Expert:  Daniel Wilson replied 1 year ago.

I asked what is the year make and model of your truck.... You never responded. I also accepted you call offer but there is a problem with your payment. You can get that resolved with customer service.

Expert:  Daniel Wilson replied 1 year ago.

Please send me a diagram of my 3406E truck. The year make and model would help. No one can give you any diagrams without that information.

Customer: replied 1 year ago.
It's a 1995 kenworth
Expert:  Andy replied 1 year ago.

Hi there . My name is ***** ***** I'd like to try and help . I need the full 17 digit vin number please .

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