Help Please

I have a P38,1996,manual, 2.5 diesel 136 Bhp, just bought it, It won't select Low range. So having read loads of threads on here and tried the following I am in need of advice.
1) Put a fuse in 11 on the BeCM was able to drop from high to neutral on the transfer box and after removing the fuse back to high.
2) took the transfer box ECU out, removed the back plate, no signs of damage or over heating, cleaned the plug and connector(which look nothing like the 55pin 2 row drawing in my manual by the way) put it back in.
3) crawled under and found the neutral selector switch, pulled the plug off and cleaned it, tried bridging said plug but nothing, put it back together.
So the conclusion is I know the motor runs and moves the selector, I can't see or smell an ECU fault so I feel it must be a dodgy neutral switch on the gear box. therefore I must be able to by pass this switch but how. My plug is a 3 row plug or am I looking at the wrong ECU. There is another plug under the passenger seat which is a 2row plug but according to my manual is for an auto gearbox.
Can some one enlighten me on how to bypass the neutral selector at the plug on the ECU which wires are they

The Transfer ECU is a 36 pin 3 row plug....

When you placed a fuse in position 11 how did you cehck for transfer neutral? By trying it in a drive gear??

There have been failures of the switch pack on the back of the Transfer Motor not giving the corect position information to the ECU....but more commonly, the TB ECU burns out first!

Get hold of RAVE as this will have the wiring diagrams in it...

Pin 34 Is the Neutral Switch....it either needs to be grounded or Open circuit - RAVE isn't clear on which position is which...the circuit diagram shows it Normally Open...so not sure!

Pin 34 should be a Brown Wire on the manual gearbox vehicle.

Thanks Saint, Yes checked the transfer box neutral by trying to drive and there was no drive. On my copy of RAVE it shows a 55 pin 2 row plug though. but now I know I have the right ECU (as I thought) and the right plug I can work out which lead it is. Working on the assumption that it's black and brown I would say black is to earth and brown will be the live side.

Saint.V8 said:

The Transfer ECU is a 36 pin 3 row plug....

When you placed a fuse in position 11 how did you cehck for transfer neutral? By trying it in a drive gear??

There have been failures of the switch pack on the back of the Transfer Motor not giving the corect position information to the ECU....but more commonly, the TB ECU burns out first!

Get hold of RAVE as this will have the wiring diagrams in it...

Pin 34 Is the Neutral Switch....it either needs to be grounded or Open circuit - RAVE isn't clear on which position is which...the circuit diagram shows it Normally Open...so not sure!

Pin 34 should be a Brown Wire on the manual gearbox vehicle.

Click to expand...

If it's normally open neutral would be closed. Only when there is a circuit through the neutral switch will ECU drive motor to low. Check interface C660/C560. Under cuddy box if they share location with later models. No location shown for 1996.

Eureka and thanks for the help. I successfully by passed the duff neutral switch.
1) took the seat cowl off and unplugged the ECU
2) located the 2 brown wires on pin34, cut one and added an extra length of wire to the plug end.
3) re-fitted the plug to the ecu, earthed the wire and nothing.
4) removed the plug again and jointed the two end of the wire back again.
5) cut the second wire and repeated the process of cutting and earthing the wire.
6) replaced the plug and tried the low range again and perfect.
This is an easy repair I have now made permanent, just have to remember not to hit the low button while driving. So much easier than trying to replace the neutral switch and chase the wire under the car.

I wouldn't call it a repair...more a temporary fix...as you should ultimatly repair correctly. but this option will get you out of trouble for now....but I would urge you complete the repair...

Top job for spotting a problem and overcoming it...great bit of detective work!

Thanks Saint, will fit a new switch when the warmer weather gets here just can't face sliding around in the cold and wet at the moment and I now have a more pressing issue. I think either the water pump or more likely the thermostat. The car over heated today(left me stranded with no phone 1/4 of a mile from home in the rain no coat either). Had a quick look and the top and bottom hoses are hot very hot but the hoses to the heater are warm only. No heat coming through the heater at all. So first thought water pump but it had a new one fitted just before I bought the car about a month ago as well as a new stat. So I feel it's most likely to the stat sticking. Checked the water and the oil no contamination at all in the header tank or rad and no contamination on the oil filler cap or dipstick. So hopefully not head gasket. Should be a simple fix I hope but if you have any other ideas I'd love to hear them.

MattSW said:

Thanks Saint, will fit a new switch when the warmer weather gets here just can't face sliding around in the cold and wet at the moment and I now have a more pressing issue. I think either the water pump or more likely the thermostat. The car over heated today(left me stranded with no phone 1/4 of a mile from home in the rain no coat either). Had a quick look and the top and bottom hoses are hot very hot but the hoses to the heater are warm only. No heat coming through the heater at all. So first thought water pump but it had a new one fitted just before I bought the car about a month ago as well as a new stat. So I feel it's most likely to the stat sticking. Checked the water and the oil no contamination at all in the header tank or rad and no contamination on the oil filler cap or dipstick. So hopefully not head gasket. Should be a simple fix I hope but if you have any other ideas I'd love to hear them.

Click to expand...

Unlikely to be the stat as the heater normally warms up first.
If both the main hoses are hot, check the viscous fan and that the RAD is hot all over. The RADS block and also the baffle in the top header fails so the water doesn't circulate through the RAD.