MBE4000 Cooling Fan Problem

Ok, first off I know I'll probably catch some slack for this but I've got a 2004 Sterling LT9513 with the MBE4000 engine in it. I've read where a lot of guys have had issues with this engine but I've honestly never had but one problem, the fuel pump went out before. Other than that, I've not had one issue or complaint with this engine, it's been great in my truck, which is a quint-axle dump by the way.

The problem I am having now however is the cooling fan. This engine has that totally useless turbo brake mess on it, but if I flip it on, the engine fan will engage. If the AC is running, once the high side pressure gets up enough, then the fan comes on until the pressure goes down. Awhile back I had some recall done on this thing, they flashed the ECM to turn the fan on with the turbo brake, an effort to make you THINK that it was doing something. For some reason, I lost all settings except medium on the stupid thing, low and high hasn't worked for a LONG time but it's useless anyway so I don't guess that matters.

If I let this truck run without the AC on or while climbing small hills or bridges or whatever, the fan will only come on if I make it come on OR if the AC is on. The temp will creep right on up to 200, it's never done this before. The fan will never come on under the control of the ECM or whatever turns it on and off. Does anybody know WTH makes that thing come on under normal circumstances? I'd love to figure out how to make that stupid turbo brake work correctly also but I doubt I'll ever figure that one out without carrying it somewhere and spending countless dollars in it.


Any help?

 

Well I've never thought much of mine, it's not that great a thing in my opinion. I wish someone would come out with a true Jake-brake to retrofit on this thing but that'll never happen. I know there has to be a sensor or controller somewhere that makes that fan work correctly. I can't find a service manual anywhere or anything like wiring diagrams or pinouts or nothing. Some people have spoke about wiring theirs onto a switch, Kenworth comes to mind here too but of course, nobody can tell me how to do it. I know it's air powered and it works with the AC or tripping the turbo brake on, so I know it's working and it's not the hub itself.

 

This is a old & dead thread but it's mine so I wanted to revive it.

I want to know how to wire the fan clutch so I can force the fan on when I want it on. If I remove the air input line, the clutch engages and the fan runs. Hook the air back up and the fan goes off. If you unplug it from the connector, it remains off. I'd like to install a switch in my dash to allow the ECM to control it normally and be able to flip it and override the ECM and force it on manually when needed.

Unplugged checking with a voltmeter, one wire has the truck voltage on it, 14 volts. The other wire shows almost 3 volts on it, odd because I figured this was a ground from the ECM. I'm afraid to experiment too much because I don't want to dry my ECM. Anyone have a clue how to do this?

 

Well, if that's the case, wouldn't unplugging it completely also cause it to come on? If I unplug it nothing changes, the fan is still "off". If I remove the air line however, it does come on.

 

And doing so, it won't hurt the ECM in any way? I'll give it a try tomorrow since I'm working nights, I appreciate the responses.

I don't understand why every truck doesn't come equipped with a manual switch for the fan...