Our 2010 Interstate has the early model, chain drive Project 2000 step. We've owned the RV for about 2 years and the step has always been a bit flaky. The usual problem is that it will not retract.
Sometimes we simply open and close the sliding door a second time and it will retract. Sometimes we've resorted to starting the vehicle and putting the transmission in gear and this will cause the step to retract. For reference, we've checked the external relay and it's working fine. We've checked the limit switch on the sliding door and it's working.
On a recent trip none of that worked and we drove with the step protruding from the side of the vehicle and were careful not to get too close to anything. Finally I took time to realize the step has a hex shape protruding from the shaft of the motor and I was able to manually retract the step.
Upon investigating the problem I think we've determined the "brain" needs to be replaced. The step operates by simply supplying 12V
to the motor and then reversing the polarity to retract the step. The brain doesn't seem to be providing the reversed polarity.
A little more detail on the polarity... The motor extends the step with a negative 12V
signal (-12V). That is, with a volt meter attached to the red and black motor leads the voltage reads negative. The polarity is supposed to switch to positive 12V
to retract the step. Our brain sends the -12V signal to extend the step but only sends a +5V signal to retract the step. The +5V will just barely move the motor shaft a fraction of a turn but it's not enough voltage to operate the chain and retract the step.
I've confirmed the motor is operating properly by placing the negative and positive voltages to the motor and it does indeed work as expected.
The replacement "brain" is going to cost approximately $250! It's the size of a pack of playing cards with two connectors.
Has anyone else replaced the brain (control module)? I think it's the same part for the old style Project 2000 step (chain drive) as well as the new gear driven step. I've seen lots of discussion about the Project 2000 step - loose set screws, stripped gears, etc. but nothing about replacing the brain.
Is there anything else I should be checking? I don't want to spend $250 and find out it was a different problem. By the way, I've been on the phone with Lippert Components tech support, they sell the Project 2000 step, and with their help I've narrowed this down to replacing the brain but there's something in the back of my mind that says I'm overlooking something.
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