Electrical Problem with Wiper Motor circuit

[StoneyHill]

I need a little help from someone who has a better understanding of the wiring of the M1009 than me.

I have looked at the Wiring Diagram on page 874 of 940 in TM 9-2320-289-20 in figure F-20. I tested the voltage at the plug before the suppressor assy. I have no voltage between the gray/white on with the column switch on low and no voltage between the purple/white with the column switch on high. I tested a working M1009 and there should be roughly 12volts there.

I understand that that usually points to the switch in the steering column. My question is this however: I have 12v across the slot for the 25amp fuse in the fuse block in the working truck. I have no voltage across the slot for the 25 amp fuse in the truck that is not functioning. Before I try to access the switch in the steering column, I wanted to make sure there is not a problem with current to the fuse block.

If it is the fuseblock, how do I test/troubleshoot it?

Any tips/help is appreciated.

Thanks,
SCott

 

[StoneyHill]

OK. I may have made some progress on my own. The right hand side of the fuse slot on the working truck has voltage to ground when the ignition is on. The right hand contact of the 25 amp wiper fuse slot does not have voltage to ground when the problem truck is switched on.

Diagram F-4 of the TM shows a wire labeled 3 BRN-4 going back to the ignition switch from that side of the 25 amp wiper fuse slot.

Is the ignition switch the problem? Can I test it without disassembling the steering column?

Thanks,
Scott

 

[StoneyHill]

Well I found the ignition switch. you have to remove the trim around the steering wheel and the instrument panel bezel. Then there are 2 metric bolts holding it up. When you remove the nuts on the sides of the steering column, then the steering column will drop down enough for you to access the switch.

I tested the right hand side of the 25 amp wiper fuse slot for continuity with the brown wire in the blue plug that plugs into the switch. I have continuity, so now the problem was either a loose connection to the ignition switch, or a bad switch.

Now I have to figure out how to release the switch from the bracket that holds it. Any suggestions would be appreciated.

I am including some photos.

 

[StoneyHill]

In case anyone is following this thread:

The metal bracket is part of the ignition switch. You have to remove the headlight dimmer switch that is on top. a 5/16 nut in front and a 3/8 nut in the rear. Then you remove the 5/16 nut in the rear to get the ignition switch off.

 

[cpf240]

I am following it, with interest, but don't have anything useful to contribute. Your pictures were helpful, as I'll be swapping out my steering column one of these days. Since I moved the tilt column out of the living room, my wife is no longer on my case about it, so I'm not in a rush at the moment.