I apologize if my answer sounded tactless. Anyway, I am very grateful that you are spending your time trying to help me. You are right to notice that language difference can convey the wrong emotion 
I tried connecting the ignition key wires, but nothing changed.
When plugged in to charge, display still dark
As I understood, one wire (Red/White) to the ignition key comes from the S6, and the other one from the diagram I see is some kind of 30 sec timer. What is that?
That Red/wht wire coming off S6 is power for your handbrake safety loop.
(Ignore that for now. This not the droid you are looking for. It has nothing to do with your Key start loop)
The Red/wht wire for your KeySw is actually coming off J2 PinJ (as noted in your diagram), and returns J3 PinA as a white wire.
It shows it going to a 30 Sec timer circuit which is inside the PSDM. This is a Delay Off timer that keeps the Acc Circuit active for 30 sec after KeyOFF.
(Ignore this for now. It is not your issue).
Key start loop needs 12v from the DC Converter. As part of my diagnostics, I look for power at S6 (constant 12v - always ON) to determine that the DC Converter is active.
(you said yes → there is power on S6)
So I turn my attention elsewhere.
You also said “all fuses are good”.
How did you test this? I assume you pulled each one and visually checked?
I would like to go to next step and test for 12v ON EACH SIDE of a couple of fuses. Do this by probing the little metal bit on the end of the fuse as it is plugged in.
The following tests are Ref ChassGnd (Black meter probe on dash metal frame)
Conditions
MainBattSwON, KeyOff, HandbrakeUP.
Verify each of the following.
Just to be thorough,
KeyON, and test S6 for 12v again.
Report back with your results.
Test results: MBS - on, Key - off, Handbrake - up
in all points (F10, F9, F5) i have 13,5 v
Key - ON:
S6 - 13,5 V
OK.
Since you have the dash panels removed, you can get access to the harness connectors plugged into the upper edge of the PSDM.
Locate J4. This is the DC Converter harness connector. Start off simple and simply remove it from the PSDM, inspect the pins for corrosion, and reinstall.
Check KeyON and Display again.
Any change?
If still not working. I’d like to check the power on this J4 connector.
This needs to be plugged in for testing, so you need to pin through the wire insulation and look for 12v (ref ChassGnd).
We know 12v constant (pinC) is active. (we see it down on S6) so you don’t need to test that.
I am interested more in PinD, which is the Acc enable. KeyON and measure PinD for 12v.
Hey, i see the problem! I know why it doesnt work! I know why it doesnt work! I know why it doest work! …your conectors must be cheap immations being lettered insread of numbered wire connection!
Good that we weren’t working on an old chariot. Those wires were labeled I, II, III, IV, V, VI
Yeah, back in those days it was jvts nvts! N-V-T-S! NVTS!
New day - back to the old topic.
Connector J4 is clean, no signs of corrosion. Reconnecting it did not change anything.
PinD (blue) has no voltage.
Clarify- KeyON, then measure PinD? = no voltage?
Then use known 12v source (S6) and run a jumper wire over to J4 PinD. You may need to strip a bit of insulation off of the blue wire.
This should wake up the Acc side of the converter.
Ok, there are signs of life
After connecting (S6) to J4 pin D, the wipers started working, the horn also, but the screen is still dark
Interesting.
Back to the Key switch.
Two wires feed into the little KeySwitch harness up near the switch.
One of them should be Red/w
The other should be W.
Meter/probe on the Red/w. (ref ChassGnd)
Do you see 12v?
Confirm (Y/N?)
If No,
Jumper 12v (from S6) over to the White wire in that KeySw harness.
What happens?
Result?
Yes, there is 12v.in that harness, bcuse w/r wire connecred to S6
Actually No. This R/w wire is connected to F5, not S6 / F10.
It is not the same wire you see connected down at S6.
A few more simple checks before I give final assessment:
That White wire goes back into PSDM on J3 PinA. Pin A should be top row/left.
Locate J3, remove from PSDM. Inspect the plug and wire going into plug for damage or other issues. Reinstall J3 and try key again.
(some people report random issues cleared by the connector remove/install process)
Verify that 12v is getting to J3/PinA by probing through insulation and KeyON.
Physical Violence
With KeyON- Rap/Tap on the PSDM in the area of the Key Relay with a screwdriver handle. The relay is under that square bump in the case.
Note: This pic is rotated 90 degrees left from how you see it in the car.
Results?
That White wire goes back into PSDM on J3 PinA. Pin A should be top row/left.
Locate J3, remove from PSDM. Inspect the plug and wire going into plug for damage or other issues. Reinstall J3 and try key again.
Done. All contacts are clear, no wire damages or corrosion.
Verify that 12v is getting to J3/PinA by probing through insulation and KeyON.
Done, there is 12V in that wire
Physical Violence
With KeyON- Rap/Tap on the PSDM in the area of the Key Relay with a screwdriver handle. The relay is under that square bump in the case.
Done. Didn’t help
Assessment:
I have not seen this failure before. The PSDM is usually a very reliable component. I am surprised.
Whatever is going on here is happening inside your PSDM module. Something between the Key return wire (White wire) and the onboard KeyON relay. It could be as simple as a bad relay (not normally a user serviceable component).
It either needs repair by a very sharp electronics guy (do NOT hand this to any average hack), or replaced from a car being parted out. I have seen them available, but sometimes expensive.
Since the factory has kept the detailed internal diagrams secret (not publicly released). Repair will be tough even for the sharp electronics guy.
This repair is also complicated by your location. (I feel you are NOT in the US?).
Hang on. before I go down the dark path, I remembered something I wanted to circle back to.
There seems to be multiple issues going on here. They might be related.
Back a few posts, I had you plug in your charger. You noted (Via charger display) that it faulted with Red(2).
Q: How long has it been doing that?
Q: Have you been doing any other work on this car lately? (specific with the charger?)
First of all, I want to answer the questions about the charger. The car stopped last September. It didn’t stop because the battery ran out. Until then, the charger worked flawlessly. I charged the batteries before winter and everything was ok. The winter was cold -13°F. In March, when I connected it to charge, the charger showed this error (2 Flash in red). The multimeter was broken, so I thought battery range too low. I charged each battery separately, but the charger still showed the same error. Then I thought that Battery range is too high. (The multimeter showed 76V). I did nothing with the charger.
I realized that I need to look for another PSDM module, because I don’t know any person who could repair it.
Maybe you can advise where I can buy a used one and how much it might cost?
Have you tried contacting FSIP? They may be able to repair it. They do the repairs for Polaris / Wavez on the controllers, so it may be worth a call.
@Anupras -
Need some background info:
Where are you located?
What is your skill set?
What is in your Toolbox?
Taco? Burrito? Whats in your speedo?
