Is this module in your coach

[Skip426]

I'm trying to import photos to a thread for the first time; so this may not work out
And of course it didn't

Any how, I'll have to do a written explanation. I have an overheating problem on my 99 DSDP Freightliner Chassis with Cat 3126b engine and side radiator.
The "KYSOR Medallion # 1539-10052 PWM Fan Control Module " had a partial failure that only allowed the rad fan to rotate at approx 20% of speed, not enough for any warm day. Because it did not fail completely the fan didn't go to default 100% operation. The reason for this post is, I've been informed by my local F/L parts depot that I got 1 of 4 remaining Modules available through F/L. When those parts are gone they will be NLS." No Longer Serviced" I haven't yet contacted F/L help to confirm this but I plan to. I can spot the failed componant on the printed circuit board; looks like a solid state relay. and plan to try and repair this for a back up part.
In the way of a warning to others that have a coach with this module. By the way it is designed, it was never intended to be mounted in a , dusty, humid inviroment; yet that's where it's mounted on my coach ! I can't tell from the wiring diagrams if F/L origially had a bag over this module the way they had others in the engine bay. If you have this module I'd say to remove it from yor coach, clean it off , and seal the cavity containing the 5 unused pins with silicone, and run a bead of silicone around the seam of the 2 part housing. Keeping moisture out will extend it's life. Rainy day when this one failed!
I'll re-post if I figure out how to import the pictures, or get a repair done.

[Mr_D]

The gasses given off by silicone is corrosive to electronics.

[Skip426]

Quote:

Originally Posted by Mr_D The gasses given off by silicone is corrosive to electronics.

Probably not as bad as the road salt spray, that got into mine. I'll look into an alternative if the new module isn't water proof. Thanks.

[Skip426]

The failed componant on the circuit board is a " mosfet" an acronym for
" metal- oxide semiconductor field-effect transistor "
Obsolete from the original manufacturer; Fairchild Semiconductor.
Looking for another source !
NOW MY HEAD REALY HURTS !

[Skip426]

Found another supplier, $3.90 for the part, I'll test all the circuits on the board then try it out with new part installed.
Online test s for the mosfet say " use caution when testing , large static discharges" now I'm sure that the dust/water on the board contributed to the failure.
New module arrived ; It's not sealed for dust/humidity eigther !!

[Skip426]

Hi guys, I've downloaded the instructions for inserting a photo to a thread, and was in the process of trying to post the photo here ; only to find the photo has been exported from my computor. Gone! No file , no record. So if by chance it has shown up some where else in the forums by my error, I appologise. I will re-read the instructions and try to be sure I don't do it again. Skip

[J Walker]

I experienced a relay for my stop lights having a problem from the elements. It was mounted near the rear wheels and water could get to it. I solved the first problem by cleaning the terminals and putting a baggie over it to prevent more spray from reaching it. Several years later it failed and I replaced it. It was a generic auto relay. I was careful to leave a way for moisture to escape from the baggie at the bottom. I feel that sealing the relay from the atmosphere might be as bad as doing nothing. BTW looking around at all of the modules and connectors and where they are placed, it is a wonder that DPs run as long as they do. What a hostile environment and there is not any extra protection beyond what the component provides itself.

[Skip426]

Jim, therein is the problem, this module provides no protection for it's self, no gel coating on the board and 5 pins through the case open to atmosphere. No sign that there was ever a bag on this module as there is on others in the area. Please don't get me started on relays ! F/L has their own design, nothing like regular automotive, at 4x the price!!

[J Walker]

I was lucky on the relay I replaced. I took the number off of the original relay, Googled it, and found it on Amazon for $6. It was a standard automotive relay.

[Skip426]

Quote:

Originally Posted by J Walker I was lucky on the relay I replaced. I took the number off of the original relay, Googled it, and found it on Amazon for $6. It was a standard automotive relay.

F/L in there infinate wisdom , decided to design there own relay, I don't know why; It's not like they were short of room! External case same as automotive; pins are 1/3 the size of automotive standard, prices varied $17>$30

[geodays1]

I had trouble with my 2001DS, fan control module, on way to factory!, stuck on side of road, called a Dealer and he informed me to unplug the fan control relay wires and the relay would fail to fan full speed!! Drove to factory with no heating problems!1.
This is a fail safe feature!, hope it helps.