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Old 06-12-2016, 10:56 PM   #15
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Join Date: Sep 2009
Posts: 427
This is for ISL 425 and maybe the same or similar for the ISL 400.

The hydraulic hoses, Comatrol aluminum valve body and the coil are located above transmission.

Engineer Mike had the technical information.

Hydraulic Valve is a poppet-type pressure relieving valve HydroForce TS38-2102 ( check part# on valve). Berenson Fluid Power. It is infinitely adjustable in a prescribed range using a variable electric input.

The variable resistance 12 volt coil HydroForce 4303712 (check part# on coil). If you have a problem, I would replace coil first and see what happens. Hydra-Power Systems stocks coil.

How it works.

The valve is in high speed fan with engine off. When the engine starts, the fan goes to low speed controlled by the ECM to increase fan speed as needed.

There is a single wire temperature sensor located directly behind thermostat housing that sends reading to ECM.

Depending on the temperature, ECM Pin 13 which has no programmable parameters sends a pulse modulated signal through a white wire to the coil to increase fan speed as needed.

When my coil my coil quit working, I began having overheating problems as fan speed would not increase. When the temperature got up to 225 degrees the fan would come on. I cut white wire to coil, put toggle switch mounted on dash to complete circuit to run on high. I could control my temperature manually fine. Do not apply any current to the white wire, only complete circuit. This told me everything worked except the coil.

When I replaced the coil on mine, it helped the overheating.

Marvin, you can PM me for more information
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2007 Apex MDTS (425 hp) #75723
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Old 06-13-2016, 08:35 AM   #16
Join Date: Oct 2009
Posts: 53
Hydraulic Oil Serviced?

It has been serviced three times in the 97K miles it has on it with the last service 5K miles ago. All three filters are changed each time so I don't think I have a problem there. Cummings is moving forward with the 100K valve train adjustment per service schedule and replacing the exhaust manifold gasket which has a very small leak. They are going to be able to trace fan control problem easier when they have the bed opened up and access is better in the next couple of days. I appreciate all the input and am checking each piece of advice offered to rule it out or fix it.

Just Cruising is offline   Reply With Quote

ems, engine, heat, problems

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