Technical Body Control or ECU or Stalk

[SB1500]

The wipers are dead. Completely.

We tested the motor, and it moves with lots of power fast and slow.
We tested each pin, and the live feed works. The earth is working. The other two (fast/slow) pins are sometimes working fine! Then they intermittently aren't.
When we plug the motor and linkage into the connectors, NOTHING happens whatsoever.
Note: The rear wiper is working when engaged via twisting the stalk, however only in normal speed regardless of which speed the stalk is set at, and if I engage reverse it will ONLY go full speed regardless of where the stalk is set at.

I'm led to believe this can now be three things;-

The Stalk Unit
The Body Control Module
The ECU

And it seems as simple as this, if it's not the stalk... it's a bloody write-off because a £400 BCM and £600 ECU simply can't happen at this stage.

What are the symptoms of each? Then we can get to the bottom of it.

 

[koalar]

Try adding a battery jumps lead from the wiper body to battery negative terminal

 

[SB1500]

koalar We tried this and earthed the motor to the chassis and it never helped sadly :-(

 

[koalar]

Was there a relay attached to the motor? Some motor have them screwed into the side for the intermittent to work. However a faulty one can stop it working altogether however they normally work except intermittent if its removed

 

[DaveMcT]

If this was the body computer I'm sure you'd have a great many other problems. Not ruling it out but it is unlikely.

My money is still on worn switch tracks within the wiper gearbox. The stalk will not see full power so check the relays that feed the wiper motor. Probably one for normal speed and one for high speed.

Intermittent puts a pulse on the motor to move the brush away from park. The motor will then do one turn and stop. Continuous running bypasses the track so the motor runs without stopping at the park position. It's likely there is are separate circuits for fast and slow.

 

[irc]

Has anyone got a good method for eliminating the wires across the bulkhead, and the connector itself? .
Just remembered that the horn stopped working properly on one of the Pandas, and it was a chafed wire in the loom. Was a bu**er to find.
Fixed it with a Heatshrink connector.
Can't check it out at the moment as all Pandas are out.
Just an idea. Not trying to add confusion.

 

[DaveMcT]

One of the first jobs - trace the loom and look for damage.

 

[koalar]

Anyone post a wiring diagram

The body computer doesn't have enough current switching capability to switch the fan on without a relay. The wiper motor as many times the amps than the fan

 

[varesecrazy]

The wipers are dead. Completely.

We tested the motor, and it moves with lots of power fast and slow.
We tested each pin, and the live feed works. The earth is working. The other two (fast/slow) pins are sometimes working fine! Then they intermittently aren't.
When we plug the motor and linkage into the connectors, NOTHING happens whatsoever.
Note: The rear wiper is working when engaged via twisting the stalk, however only in normal speed regardless of which speed the stalk is set at, and if I engage reverse it will ONLY go full speed regardless of where the stalk is set at.

I'm led to believe this can now be three things;-

The Stalk Unit
The Body Control Module
The ECU

And it seems as simple as this, if it's not the stalk... it's a bloody write-off because a £400 BCM and £600 ECU simply can't happen at this stage.

What are the symptoms of each? Then we can get to the bottom of it.

didn't this all start with the scuttle full of water..??

some info ;
https://www.fiatforum.com/panda/424601-wiper-problem-moody-wipers.html

https://www.fiatforum.com/panda/440827-big-big-problem.html

 

[koalar]

Has anyone got a good method for eliminating the wires across the bulkhead, and the connector itself? .
Just remembered that the horn stopped working properly on one of the Pandas, and it was a chafed wire in the loom. Was a bu**er to find.
Fixed it with a Heatshrink connector.
Can't check it out at the moment as all Pandas are out.
Just an idea. Not trying to add confusion.

Leave the device that's not working connected. Switch the device on while measuring the back of the connector. Positive of the multi metre on the connector and negative lead on the chassis.


If you can't get a probe on the back of the connector you can pierce the insulation with a pin.


Removing the connector and you can still get volt even If there is a short elsewhere. Can lead you to be chasing shadows. Always try and measure from the back of the connector.

 

[jrkitching]

And it seems as simple as this, if it's not the stalk... it's a bloody write-off because a £400 BCM and £600 ECU simply can't happen at this stage.

Not necessarily if you think outside the box.

If all else fails, put a simple toggle switch somewhere on the dash and label it "wipers". Hardwire it to the battery (with an inline fuse) and the normal speed connection on the wiper motor.

You'll only have 'on or 'off'' wipers like in the old days, but it'll be enough to see where you're going when it's raining and it should be enough to pass an MOT.

 

[koalar]

Operational description
The steering column switch unit H005 sends the commands to the body computer node M001 to activate the motor for the windscreen wiper and windscreen washer by means of a negative signal, with reference to the earth C020 connector B (from pin 2 connector B of H005).


Earth C020 is secured to the passenger compartment floor and is positioned near the right front wheel arch (footwell area).



Turning internal switch A of the steering column switch unit:

position 1 (pin 8 connector A): activates windscreen wiper speed 1;to

position 2 (pin 7 connector A): activates the speed at intermittent (speed 1);to

position 3 (pin 9 connector A): activates windscreen wiper motor speed 2.to

The body computer node also activates speed 2 when internal switch B of the steering column switch unit is turned to position 1 (anti-panic function). to

Depending on the command received, the body computer node:

activates speed 1 by supplying the windscreen wiper motor N015 from pin 9 connector B;to

activates speed 2 by supplying the windscreen wiper motor N015 from pin 10 connector B;to


Power to the windscreen wiper motor is supplied from the body computer node and the line is protected by fuse F43 contained inside the same control unit. The fuse is controlled from a relay built into the body computer node; this supplies power, according to the desired speed, to the windscreen wiper motor from pin 9 or 10 connector B.



At pin 8 connector C, the body computer node receives the wiper arm end stroke signal from the windscreen wiper motor N015.

Turning the internal switch B of the steering column switch unit H005 to position 2 (pin 6 connector A), activates the windscreen washer function. The body computer node M001 from pins 3, 4 connector B supplies the power to the windscreen washer pump motor N002 . The power supply line is protected by fuse F53, housed inside the body computer node and controlled by a relay built into the same control unit.



Does appear as the relays is built into the body computer. Thought you got volts so you could try cleaning the earth bolt

 

[Most Easterly Pandas]

Note: The rear wiper is working when engaged via twisting the stalk, however only in normal speed regardless of which speed the stalk is set at, and if I engage reverse it will ONLY go full speed regardless of where the stalk is set at.

With rear wiper switched off and front wipers in the 'active' (either intermittent, constant or fast), when in reverse does the rear wiper operate?

If it does then this rules out the switch unit.

 

[SB1500]

With rear wiper switched off and front wipers in the 'active' (either intermittent, constant or fast), when in reverse does the rear wiper operate?



If it does then this rules out the switch unit.

Yes, I can confirm it will operate in this way.

So the motor is fine. The stalk is fine.

Body Control Module then???

 

[g8rpi]

Probably BCM Assembly, or connections to motor. Don't forget this includes connectors, fuses and relays so check those first.

Robert G8RPI

 

[Most Easterly Pandas]

:yeahthat:

 

[SB1500]

We checked the fuses, they're fine.

As it died out eventually, we can't see it being a fuse.

We saw the wide grey connector on the BCM with the other end of the wires at the motor. We contact sprayed this. But if it's this connector, then why aren't all the other wires and their associated parts not playing up??

Can I just buy a new BCM or is it associated with the ECU and difficult?

 

[koalar]

Did you check the single wire connected to the body in the passenger footwell.

 

[irc]

You might want to do a continuity test on the wires identified in koalar's post. Can't post much description now, but sure one of the others can suggest best method.
Test from the wiper motor loom connector to the BCM connector with both ends unplugged. If you get high resistance then problem is loom related and can be fixed very cheaply.
If you don't, then points to relays in BCM having problems.

 

[portland_bill]

The column switch just sends a signal to the BCM (Body Control Module). The BCM then interprets this and sends power to the wiper motor, either 1st or 2nd speed, as requested. This should result in battery voltage arriving at the relevant pin at the motor connector. It would appear that this does not happen.

Finding a small voltage momentarily, suggests that the BCM is trying to do its thing, but failing. This could be an internal 'relay', which might be an actual relay built into the BCM circuit board, or it may use transistors. Or the problem might be just a poor connection at the BCM grey plug. With the plug removed, you could try to read the output voltages at the relevant pins that supply the two motor speeds. If these give battery voltage, then the problem lies with the connectors or wiring. If the BCM output is incorrect, the problem is within the BCM. Opening up the BCM might show a fixable fault, or might just destroy it.

The body control module has to be made to talk to the ignition ECU. It contains the code for the ignition key, and has to match the same code stored in the ignition ECU. When either module is replaced, they need to be told to talk to each other. I'm not sure that MES can do this as key security is involved.

Alternative.
From the scrap car, you'd need both ECUs, all the keys and locks. Then the ECUs think that they are on the original car, although any CanBus modules on the car might need a proxy alignment to make them communicate with the 'new' ECUs.
This will also add a challenge regarding mileage. If the 'new' module contains a mileage higher than yours, it can only make the car read the higher figure. If the car is higher, I think a proxy alignment will tell the ECUs to accept the higher figure.

Next issue. The replacement module set needs to be same spec car, or higher. You can turn off functions in the ECU, but not add them.
e.g. If the donor car has front foglamps, and the recipient does not, MES can turn off the front fog function.
But, if the recipient has front fogs, but the donor did not, they'll never work again, as this function cannot be added by MES.
This applies to any and all functions, including electric windows, central locking etc.

Unless anyone knows better.