How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Alex Olsen Your Own Question
Alex Olsen
Alex Olsen,
Category: Medium and Heavy Trucks
Satisfied Customers: 93
Experience:  Lead technican at Astleford international trucks
96118949
Type Your Medium and Heavy Trucks Question Here...
Alex Olsen is online now
A new question is answered every 9 seconds

2009 International 4300 Dt466 Fan clutch stays engaged at

Customer Question

2009 International 4300 Dt466
Fan clutch stays engaged at all times. need to know if the engine coolant temp sensor is the same thing as a Thermal Switch.
Submitted: 23 days ago.
Category: Medium and Heavy Trucks
Expert:  Alex Olsen replied 23 days ago.

hi I'm alex could I get the last 8 of your vin?

Customer: replied 23 days ago.
9h163642
Expert:  Alex Olsen replied 23 days ago.

OK thank you

Expert:  Alex Olsen replied 23 days ago.

Looks like this is a Horton drive master 2spd

Customer: replied 23 days ago.
ok. I am inside of a bay and don't get great reception.
Expert:  Alex Olsen replied 23 days ago.

I have terrible reception where I am at as well, I can call whenever it is convenient

Customer: replied 23 days ago.
now or chat. it don't matter
Just need the proper diag for this truck
Expert:  Alex Olsen replied 23 days ago.

Do you have any software to read ECM or body controller?

Customer: replied 23 days ago.
Jpro
Customer: replied 23 days ago.
But currently not with the truck. Back to the question though. I have continuous air coming out of the Fan Solenoid to the fan clutch. Need to know what the Thermal Switch is?
Expert:  Alex Olsen replied 23 days ago.

Coolant temp sensor? where are you getting thermal switch from?

Expert:  Alex Olsen replied 23 days ago.

Fan is controlled by both the ECM and body controller for a/c

Expert:  Alex Olsen replied 23 days ago.

It doesn't have high coolant temp I assume

Customer: replied 23 days ago.
A/C high pressure switch and the thermal switch. that is the information that I have found. Thermal switch I was think was a veg term for coolant temperature.
Customer: replied 23 days ago.
No high coolant. Fan was on at 135 F according to JPro.
Customer: replied 23 days ago.
Fan stays engaged at all times. I pulled the air line from the solenoid and I have continuous air out the solenoid. I unplugged the two prong plug conector from the solenoid and the air stops..... All this while the truck is under 140 F
Expert:  Alex Olsen replied 23 days ago.

Ok seems to me the body controller is probably requesting fan on for high a/c pressure

Expert:  Alex Olsen replied 23 days ago.

Does not mean it actually has high a/c pressure but body controller might think it does

Customer: replied 23 days ago.
all with the A/C off.
Expert:  Alex Olsen replied 23 days ago.

Yeah it is possible body controllers sometimes have a mind of there own

Customer: replied 23 days ago.
ok in short truck needs to go to the dealer and have the BCM Diag
Customer: replied 23 days ago.
The operation isA/C High pressure switch
Thermal Switch
ECM
Fan Clutch Solenoid
This is all according to Horton Tech Document
Expert:  Alex Olsen replied 23 days ago.

Yeah if you have power at the solenoid something is requesting fan on. Do you have a fan status parameter on your jpro

Customer: replied 23 days ago.
it is bi directional but no commands for the fan. I will have to contact Jpro people to ensure I have it.
Customer: replied 23 days ago.
To recap, you don't think that it is a Thermal Switch or Coolant Switch, it is the BCM
Expert:  Alex Olsen replied 23 days ago.

Yeah like in servicemax we have a fan status parameter and it will say like "a/c" when fan is on because of a/c high pressure

Expert:  Alex Olsen replied 23 days ago.

Well its not showing high coolant temp and that's what the ECM looks at for fan control

Expert:  Alex Olsen replied 23 days ago.

You have 12 v at the solenoid all the time right

Customer: replied 23 days ago.
that is correct. all while under 140 F
Customer: replied 23 days ago.
Ok I am good from here we can end the session.
Expert:  Alex Olsen replied 23 days ago.

We can keep it open if you need more help

Customer: replied 23 days ago.
I would like more info. I have mitchells and the wiring diagram don't show a BCM, just the ecm.
Expert:  Alex Olsen replied 23 days ago.

Was the solenoid replaced?a normally closed solenoid in place of a normally open one?

Customer: replied 23 days ago.
anyways I am loosing money on this. I will contact the owner and will give him the update. It still needs a new fan Clutch.
Customer: replied 23 days ago.
I have no past information on this truck.
Customer: replied 23 days ago.
if it was it would shut off when I unplugged the wiring
Customer: replied 23 days ago.
I am sure that it is the correct Fan Clutch Solenoid
Expert:  Alex Olsen replied 23 days ago.

If you have it hooked up to DLB software it will tell if BCM is requesting fan on

Customer: replied 23 days ago.
ok we can end the session now. thank you for your time.
Expert:  Alex Olsen replied 23 days ago.

Your welcome

Expert:  Alex Olsen replied 19 days ago.

please remember to rate my service when you get a chance, i will continue to assist you after rating so rate with confidence, Thanks