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Benw82
12-09-2013, 04:31 AM
I have a 2003 sprinter and have been dealing with fan issues for a while.
Did some searching and couldn't quite find the answer.
My blower motor went out so I ordered one from europartsSD and all was good for a few weeks(Only on level 4). Yesterday the fan randomly goes out completely cruising down the interstate. When I can hard wire the fan to the battery and the motor operates as it should. I also checked the voltage at the end of the fan connector with the dial set to 4 and it reads 13.0 volts.... but, plugged in to the fan, NOTHING...

just trying to figure out what part to replace next. i wouldn't mind getting it set up with a simple on/off switch and bypass all the faulty wiring

autostaretx
12-09-2013, 04:54 AM
This thread discusses testing and repairing the blower resistor block: http://sprinter-source.com/forum/showthread.php?t=17928
Message 35 in that thread has the resistor block's resistor values.
There is also a "fusible link" across the top which can open.

The same topic is rehashed in this thread (more diagrams, more comments): http://sprinter-source.com/forum/showthread.php?t=27941
See post 7 for the two possible wiring configurations.
The 2003 Service Manual is available here: http://aie-services-2.net/Sprinter/

Intermittents could also be the fan motor brushes, or perhaps the relay.
And the relay is another kettle of fish: http://sprinter-source.com/forum/showthread.php?t=29749

(pre-s: i used the words "fan resistor" in the Search function of the forum's blue bar to find the above)
good luck
--dick

bc339
12-09-2013, 08:16 PM
One item that gets overlooked is the connector at the back of the ATC. There are two connectors - one on the left and the other on the right. The fan connector is on the left side of the ATC and has about five large gauge (12ish AWG) wires.
If it is not fully seated, your fan speed and operation may have the same symptoms you have described.

Bruce

bruceiam
12-09-2013, 10:19 PM
I had the same problem with my 2002 Freightliner. I took the resistor assembly out and found the tin frame work that supports the resistors had cracked. I covered the crack with solder and intended to order a new one. It hasn't given me a problem in over a year so I'll call it fixed.

Benw82
12-11-2013, 12:57 AM
Bruce, what is the ATC?

I also discovered that my fan works when using the REST function but only when the fan dial is on 4...
Does that help me figure this out?
Also took out the resister assembly and it looked in good shape. No obvious cracks or wear.

bc339
12-11-2013, 01:23 AM
The ATC is the Automatic Temperature Control, or the control panel in the center of the dash with the three controls for temperature, vent position and A/C, heater controls.

When you select the REST, the fan speeds will be reduced - with the fan speed knob selected in 4, it is like 2 when the engine is on. Selecting the fan speeds 1 and 2 will be the same as 1, 3 and 4 will be fan speed 2 or thereabouts.

This thread will describe how to disassemble the center console to remove the ATC: http://sprinter-source.com/forum/showthread.php?t=28558

If you don't have a copy of the service manual, you can grab one here: http://sprinter-source.com/forum/showthread.php?t=26431

Bruce

autostaretx
12-11-2013, 03:42 PM
I also discovered that my fan works when using the REST function but only when the fan dial is on 4...
Does that help me figure this out?
Also took out the resister assembly and it looked in good shape. No obvious cracks or wear.

When the speed is at 4, the resistor is removed from the system (the switch replaces it with a piece of wire).
Therefore, it's really really likely that it's the resistor that's at fault.
They can "look" fine, but only an ohmmeter can tell you what's going on inside.

--dick