Overheating because fan won't come on

I had a 2005 Frtlnr chassis with side radiator. It had a tendency to overheat. I took it to Gafney, SC, Frtlnr motorhome guys. From the factory the fan modulator was missing. the main thing I learned was that the radiator and cooling system were marginal and the rpm's had to be kept between 1800 and 2100 while in any kind of grade or steep terrain. This was more evident in the earlier chassis, but it solved the problem.

Freightliner should be able to plug their computer into the data port and check the fan signal out of the computer/controller.
Then you have the wiring and hydraulic servo valve in tthe circuit.
Course you need good hydraulic pressure as well.

Please keep us posted.

Call Freightliner 24/7 Help Line. Forget his email ****.
If it is on a FL chassis then They know all about it.
When you call, be at the shop, then speaker phone.

Our fan does not work at all. The shop has talked to Tiffin and freightliner and are still diagnosing.

Call Tiffin service department. It's faster resolving problem when speaking with a service rep.

Here is a product to eliminate some of the issues with the side radiator coaches. It senses the temperature of the coolant at the thermostat and tells the engine fan when to come on. It will allow the engine fan to run at variable speeds, which will increase mileage.

Take a good look at this product as a solution to your problem.

Source Thermal valve

Freightliner Gafney 800 385-4357 need VIN

They designed and built your chassis, including cooling package.

I emailed Tiffin. Freightliner Chassis. And yes, to last question.

Can you call Tiffin?
Is it on a Freightliner chassis?
Is yours a side radiator driven by a hydraulic motor attached to the fan?