155-54 TZ transmission electrical fault

Hi I am new to the forum I hope my English translates to French okay for those of you not in the UK. I have a 1995 155-54 TZ with the three speed power shift gear selection. It has recently developed a discharging fault and after closer inspection I have found that all the electronic solenoids on top of the gearbox are constantly live with 12 volts even when the ignition is switched off. I notice that the gearbox wiring receives power directly from the battery and when this wire is disconnected and reconnected it resets the problem and the solenoids are off until the ignition is activated and then switched off again and the problem is still present with 12 volts constantly showing. All the solenoids appear to be the same and obviously cause the discharge problem. When driving the tractor it will not change gear and it remains in the medium range. when I try to change the shift light moves and then reverts back to medium. I have already had the processor / brain off and somebody has inspected it and can find no fault. I have also fitted new terminals to the wires onto the battery for the gearbox feed and I cannot find a relay or anything as I thought something might be sticking. Any ideas or suggestions are welcome please. I'm fairly new to Renaults so just learning. Many Thanks

Hi Renaultman !
My name is Jack and Welcome to the Renault Tractor Association forum.
I shall try to bring you some help with your faulty machine. Could you send us your tractor serial number: in fact during the building life of this tractor type, some changes occured and I need to know exactly which feature was made your tractor with.
I can advise you to get with technical documentation thanks to R.T.A if you could have a good opportunity to translate a french information. In case of necessity, you will send an email on the R.T.A mailbox written in forum ahead asking for technical books relating your Renault 155.54 TZ tractonic tractor. You will be answered shortly with name and price whose you only have to order about and pay by bank transfert mean.
Mainly, the disfuntioning of the tractonic transmission is caused with bad electrical conections linked to pollution and wet mud between the cab and chassis. In that way, that's necessary to clean up and dry this area as well before engaging diagnosis.
Do you have any possibility to set an exchange Electronic Control Unit (ECU) coming for example from a neighbour customer tractor even a less powered machine until to be sure with the faulty parameters you've described on.
In the opposite you seem to understand, there are two types for solenoids five of them called ON-OFF simply provided 12v to action and the two last one to the middle at the front of the hidraulic block which are proportional valves offering one gradual pressure into the clutches for soft engagement. All of them are directly controled with ECU. The ON-OFF ones receive a permanent 5.6v in the aim of checking short  or cut circuit after the ignition should be switched on. The proportional valves are driven with an increase intensity up to 2.2amps.
I make you this proposal after cleaning at all over the gearbox housing to check every conections for valves and sensors marked with colored rings. Then you will remove the round plug fitted just closed to the left hand side ladder connecting the two half part of the tractonic specifical wiring. Try to test it after exit of casual pollution.
Tell me please if this tractor has ever been reworked by mechanic  and the diagnosis lamp is flashing quickly (red one at right side the Dashboard)
I remain to your disposal as needed.
Best regards = Jack72

Hi thanks for your reply. I think this is the serial number- 5291621. The tractor does not work in any real wet or muddy conditions and has not been near anything corrosive such as road salt or slurry. Unfortunately I don't have access to another ECU so I cant do a swap to be sure of ruling that out. The tractor has now started driving again and will change through the three ranges but still has the discharging fault and will not cut the power to the solenoids once the ignition is off. I will check that multi pin plug under the cab at the weekend. Thanks again.
Joe

Hi Renaultman! I feel very happy you've been answering so quickly and precisely! Could you confirm however this tractor was reworked by some CLAAS mechanic or not and in that case which part was fixed ?
You told me this tractor seems to be again working as well changing the three ranges: maybe could you precise what has been done to get such that result? (removing of one wiring or something else ?)
Today through this permanent discharging fault, is there any warning light blinking to the dasboard (diagnosis one for TRACTONIC) ?
If you remove the intermediate round plug, you'll be seeing at seven lines of pin from 4 at the top to 2 at the sixth line at botom. The third line with six pins are concerned with direct valves and earth.(From left to right 10 to 14; 15 for earth)
An other point may have been reconnected in wrong way speaking on the specific tractonic warning lights bar : there are 9 connections to these indicators whose first one (diag) has 2 cables and the first to be connected to the right place is 12v BAT in red color.  As noted by yourself, there is a specifical connection to the positive point of battery protected through one 7amps fuse: So it means somewhere, after switching off igniton, there is still a link between this connection and wiring to solenoids ?!?
I think it should be better having the workshop manual to get with a clear view onto the circuit.
Could you select today the typical drive "go & return" as described into your user book ?
At least I remain to your disposal with my hope to solve your problem.
Best regards = Jack72