Have intermintent fault in EPS gearbox wiring,mostly 4th-5th gearchange, can anyone supply wiring diagram or advise on each gear solenoid location / pin location in cable plugs so I can check continuity.
Thanks Geoff
Have you got a chassis number/reg number?
TDL102 hope you can help as I have 3 of these 
Chassis no WDB6531582K221975
When you say intermittent fault in wiring is it bringing a fault up or is it dead slow to shift, it’s changing range from 4th to 5th and sometimes the piston used to stick in the cylinder the range change, or the seals fail. Also there was a 14mm plug which would sometimes work loose on the cylinder leaking air causing a slow shift or none at all.
Where are you based as I have some diagnostic kit which should still work on it.
Attached (hopefully) is a wiring diagram for the EPS gearbox
The chassis number comes up on the Mercedes Parts EPC (electronic parts catalogue), so if you pop into a Merc dealer they should be able to look it up and show you around the parts you might need to check.
regards
Sorry Tdl102 that diagram is a parts picture not a wiring diagram, I might have one in the garage but you will have to wait till I have a turn out!
“position fingers” are a problem with old EPS box.Two detents fit in the gearbox turret and tell the box control what gear is selected.Sometimes one of them gets sticky and the box doesnt know what gear is engaged so shifts to neutral
Take them out and give them a clean.
I’m in New Zealand, diagnostic tool couldn’t connect so had to go off fault codes (049). Speed sensor wiring was repaired but problem still exists. If I had diagram of solenoid/sensor layout would help. Sometimes box would miss 5th go straight to 8th. Local Merc dealer only had dealership 12yrs so limited and unhelpful .
I still reckon its a mechanical fault not an electrical fault from what you are saying, does it carry out a re-programme ok? If it has an open circuit or short to pos or neg it would have a current fault flash up and the gearstick would click repeatedly. I would pull the range change cylinder off the top back of the box first, check and lube the seals with rubber grease. Check the gear and gate sensors on the cross shaft at the top front aren’t worn or sticking. They did have selector shaft problems with the c clips breaking but is a big job with removing the right gearbox mtg and a special tool to rebuild the shafts together. Also the gear cylinders used to ■■■■ oil in and hydraulic lock some times.