PRND selector fault - Only goes forward
Posted: Mon Sep 24, 2012 11:33 am
An embarrassing moment today when I came to select reverse the Blingo just went forward. Thats odd I thought and went through all selections hoping to see the reverse yellow light come up on the dash. But it only lit when I selected Park. I had to wiggle it around so that it was just out of Park (so the pawl wasnt engaged) and still giving some reverse. Got out of trouble and decided I needed to strip down the selector to see whats what.
After removing the trim round the handbrake and the selector lever you can undo 4 small machine screws on the side of the selector lever and open up the hole where the business end of the selector is.
This appears to be a simple mechanical link to the Park pawl and a black device mounted on the drivers side with two wires leading to a small plug. It would seem that as you move the selector what you are really doing is changing the resistance of a two connector pottentiometer. One end is connected to 12 volts from (I guess) the ECU and as you move the selector this voltage rises and falls as more (or less) resistance to ground is in circuit.
This "pot" measure 200 ohms to 2Kohms from end to end. It seemed to adjust smoothly and vary the voltage on the line back to the ECU - but alas no reverse.
Anyone experience anything similar - all help appreciated.
John
After removing the trim round the handbrake and the selector lever you can undo 4 small machine screws on the side of the selector lever and open up the hole where the business end of the selector is.
This appears to be a simple mechanical link to the Park pawl and a black device mounted on the drivers side with two wires leading to a small plug. It would seem that as you move the selector what you are really doing is changing the resistance of a two connector pottentiometer. One end is connected to 12 volts from (I guess) the ECU and as you move the selector this voltage rises and falls as more (or less) resistance to ground is in circuit.
This "pot" measure 200 ohms to 2Kohms from end to end. It seemed to adjust smoothly and vary the voltage on the line back to the ECU - but alas no reverse.
Anyone experience anything similar - all help appreciated.
John