Community Forums

bigdog · 07-18-2016, 12:10 AM

I have heard that there is a way to cheat the high speed hydraulic fan control to make it run full speed, but I can't figger out how it's done. The engine needs to be above a certain temp for it to kick in is what I was told. In the school bus I used to drive, you could usually hear it roar when it kicked in, but in a MH, it's usually pretty well silenced.

DJJ · 07-18-2016, 05:37 AM

Follow the wiring from the pump to the frame rail, only about 12" from the pump will be a 2 wire quick connect and a single wire quick connect. Unplug the 2 wire quick connect and the pump will default to high speed. The single wire tells the pump to pick up speed when the A/C is turned on via a pulse signal, so unplugging the single wire quick connect won't trick the pump.

At least on my 03' it works that way.

Jeff

bigdog · 07-18-2016, 11:48 AM

Thanks, I'll have to give that a look.

Rich-n-Linda · 07-18-2016, 10:11 PM

If you make the pump run on high speed all the time, it will cost you about 1 mile per gallon. Been there. Done that.

It It takes a lot of horsepower to run that fan on high all the time.

Don't do it.

bigdog · 07-19-2016, 12:35 AM

No, I just wanted to know if it was operating or not. I had a friend whose MH was overheating on hills and he found that the fan wasn't cutting in at the higher temps as it was supposed to. He was having to depend on downshifting to bring up the engine rpms and get the fan turning fast enuff to bring the temps down. that in turn slowed down his speed.

Rich-n-Linda · 07-19-2016, 09:41 PM

I have dealt with this issue on our Mandalay. The coach is in the shop right now with a fix being installed. I intend to post a detailed explanation about my experience when the work is all done.

I had the same symptoms...the fan would not go to high speed.

Gary RVRoamer · 07-22-2016, 10:18 AM

Odd that it failed "slow", since the controller defaults to full speed. The control functions all cause it to slow down.

My '04 XCM chassis (ISL engine) has a variable speed fan controller, but some FTL chassis years/models use a simpler 2 or 3 speed control. In fact, some older ones (mechanical engines) were just single speed.

Rich-n-Linda · 07-22-2016, 05:20 PM

In my case the solenoid which engages to put the fan on high speed is what failed. It has just been fixed, but the coach is in the interior shop for new carpet now.

When I get it back and can confirm temps with Silverleaf, I intend to post a detailed description of the whole episode.

Skip426 · 08-16-2016, 10:22 PM

Quote:

Originally Posted by Gary RVRoamer

Odd that it failed "slow", since the controller defaults to full speed. The control functions all cause it to slow down.
.

I've had the fan speed control module fail twice on my coach and both times it failed to slow .

The original module's circuit board , was repairable, and installing a $6 MOSFET ; can't remember what the acronym means, transistor is the T; and kept it for a spare . Luckily, because the new $235. controller failed after the 1 year warranty and is not repairable , all surface mount components on the circuit board.

Don't know how many years Freightliner used this exact module , but three years ago when I bought the new one , there were only 4 left in the system.
So if you need one of these : photo below : see about repair if possible.

stratob377 · 09-17-2016, 09:22 AM

Just had that changed out lastnight in buffalo (medallion). Module failed to 0 rpm just after leaving newmar in nappanee last week. Pulled into schmuckers propane and pulled the 2pin connector apart, ran home on high speed. You can still get the medallion part. $187.

"Don't know how many years Freightliner used this exact module"

Skip, when I talked to FL last week, sounded like 2005 was the last year.

Skip426 · 09-18-2016, 09:20 AM

Quote:

Originally Posted by stratob377

"Don't know how many years Freightliner used this exact module"
Skip, when I talked to FL last week, sounded like 2005 was the last year.

stratob377.
I figured they would be making more , thanks for the, years of usage info.
The price I paid was here in Canada , so in line considering exchange rates.
First picture is the original module circuit board , with the failed transistor circled.
Second is the failed replacement. My friend ; who repaired my original circuit board ; looked at the newer board and gave it the not repairable diagnosis .

He worked in aircraft electronics for 35 years , so I'll take him at his word.
If you open the housing and find your board looks like my original , and don't want to try a repair on it , PM me and we'll discuss a price and shipping it to me , sometime this winter, while I'm in the USA . I'd like to have one for back up.

stratob377 · 09-23-2016, 04:03 PM

Ours went boom pretty good

ransil · 09-23-2016, 06:41 PM

The new surface mount on looks like the same circuit as the older one, just surface mount components. Does look like they did at least glue down the big parts as they tend to fall off during shake & bake testing.
Ouch on the price, in a decent order quantity that caNt cost more than 30 to manufacture