OP
OP
Technical Body Control or ECU or Stalk
- Thread starter SB1500
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Technical Body Control or ECU or Stalk
Output at each of the BCM pins should be battery voltage, constant as long as switch is in 'on' position, as this drives the motor. A momentary voltage will only move the motor a little, and if far enough, it will continue its sweep using the park supply.
Initially I would try to probe the connectors with your voltmeter to check for a voltage. If the BCM output appears OK, then you can consider your by-pass, but the problem is unlikely to be along the cable length, but at the connectors. So cleaning the connectors is likely to be a cure.
If you need to replace the wires, cutting the originals may make life difficult in future. The actual connectors in the plug may be available off the internet, if they can be identified. Look for a maker name on the plug, or a label on any wiring, as there are only a few loom manufacturers, and they tend to use the same connectors. Vehicle manufacturers will need to be able to source looms from more than one supplier, so will usually insist on 'standard' connectors. Releasing the old ones is always a challenge. Finding the little barb that holds it in is difficult, then finding a tool to release it, another challenge. A pin or needle from a sewing kit may help. Or may just stab you.
Initially I would try to probe the connectors with your voltmeter to check for a voltage. If the BCM output appears OK, then you can consider your by-pass, but the problem is unlikely to be along the cable length, but at the connectors. So cleaning the connectors is likely to be a cure.
If you need to replace the wires, cutting the originals may make life difficult in future. The actual connectors in the plug may be available off the internet, if they can be identified. Look for a maker name on the plug, or a label on any wiring, as there are only a few loom manufacturers, and they tend to use the same connectors. Vehicle manufacturers will need to be able to source looms from more than one supplier, so will usually insist on 'standard' connectors. Releasing the old ones is always a challenge. Finding the little barb that holds it in is difficult, then finding a tool to release it, another challenge. A pin or needle from a sewing kit may help. Or may just stab you.
OP
OP
This is the latest plan:
This Week:
Fit the adjustable power control switch to gain some control over the wiper speed. Continue on with the England road trip and into the New Year.
January
Fit another linkage/motor unit and test connector (see if it works)
Fit a new steering stalk unit and test connector (see if it works)
And if none of those fix it, then we will follow portland_bills advice to see if its the wire or BCM.
Then it's a matter of fix the wire, or live with it.
The guys who I'm sourcing my parts from reckon that it's very common for the stalk unit to be at fault. This seems to be most peoples knowledge. Seeing as I thought I knew it was fine but in fact, don't, it could be the miracle cure I'm hoping for!
This Week:
Fit the adjustable power control switch to gain some control over the wiper speed. Continue on with the England road trip and into the New Year.
January
Fit another linkage/motor unit and test connector (see if it works)
Fit a new steering stalk unit and test connector (see if it works)
And if none of those fix it, then we will follow portland_bills advice to see if its the wire or BCM.
Then it's a matter of fix the wire, or live with it.
The guys who I'm sourcing my parts from reckon that it's very common for the stalk unit to be at fault. This seems to be most peoples knowledge. Seeing as I thought I knew it was fine but in fact, don't, it could be the miracle cure I'm hoping for!
Just checked on my car. 1.2 on a 05
Ignition on
Radio off. Heater off.
Lifted the wipers off the screen.
Head down by the pedals.
Reached up and operated the wiper stalk. The relay in the body computer can be heard to operating. Faint but quite clear.
Ignition on
Radio off. Heater off.
Lifted the wipers off the screen.
Head down by the pedals.
Reached up and operated the wiper stalk. The relay in the body computer can be heard to operating. Faint but quite clear.
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When I have the front wipers on and twist and turn on the rear wiper, it works one wipe for every two wipes of the front wiper at speeds one and two, so yes it speeds up with the front wipers. Can't comment on speed 3 as I never use it.
If the front wipers are in use and reverse is selected, the rear wiper comes on fast regardless of whether it is switched on or not.
OP
OP
Just arrived back in Northern Ireland tonight.
Got my Stalk Unit and new wiper linkage and motor sitting in the boot. Will talk to my uncle in the next few days to see when we're fitting it. Not sure if it'll be before or after Christmas.
Hopefully it'll be the miracle cure!
Got my Stalk Unit and new wiper linkage and motor sitting in the boot. Will talk to my uncle in the next few days to see when we're fitting it. Not sure if it'll be before or after Christmas.
Hopefully it'll be the miracle cure!
OP
OP
Thanks to everyone who checked their wiper function, helps!
This is normal operate, 1 swipe of rear for 2 of the front regardless of speed, as such with front on fastest speed the rear is almost on constant with a very small fractional pause in-between its wipes.
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How much doe the BC really do with managing the front wiper? I suspect apart from the intermittent and wash (double wipe) not very much. Why do I say that? Put the wipers on and there's a slight almost undetectable delay and they start. Makes sense as the BC does it's thing. Put them on flick wipe and they instantly fly across the screen. Even the slightest flick of the switch and they jump into action.
I suspect there is little and maybe no processing between the stalk switch and relay that drives the wiper motor. If I'm right (and it is a guesstimate) your problem may be just the BC relay.
Fit the new stalk then listen for that relay clicking. Even better work out which stalk contacts trigger the relay for flick wipe and jump them with a voltmeter set to the current scale. If nothing happens change the relay and try again.
I suspect there is little and maybe no processing between the stalk switch and relay that drives the wiper motor. If I'm right (and it is a guesstimate) your problem may be just the BC relay.
Fit the new stalk then listen for that relay clicking. Even better work out which stalk contacts trigger the relay for flick wipe and jump them with a voltmeter set to the current scale. If nothing happens change the relay and try again.
OP
OP
When I put the stalk on, you can still hear it clicking away. Just, nothing happens.
Where is the relay on the BCM exactly and can it be changed and how?
We have not yet changed anything since my posts last week. Going to take the parts up to my uncle later to show him them. To be honest, the BCM is perfectly coordinating the lights, rear wiper, washer jets etc so I don't like to think it's that either.
It's just.. if these parts don't fix the problem, the BCM is all that's left as a culprit?
AIUI the relay is integral with the BCM so is presumably a miniature surface mount relay soldered to the BCM PCB.
This is exactly what I would expect to see if the problem was caused by a faulty wiper relay in the BCM. Only the function controlled by the failed relay would be affected.
OP
OP
jrkitching , would it be worth trying to replace the relay should it come to this?
Front and rear use different fuses and relays.
If you can hear the relay operating just with the front operating it is highly unlike there is a problem from the stalk to the body computer or with the body computer.
Problem is more like output wiring motor and earth.
Original going slow sounds more like earth wiring or motor
If you can hear the relay operating just with the front operating it is highly unlike there is a problem from the stalk to the body computer or with the body computer.
Problem is more like output wiring motor and earth.
Original going slow sounds more like earth wiring or motor
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OP
OP
In order to triple-check and fully check that Earths aren't the problem, is anybody able to explain all of the relevant fuses that need checked, we checked about 4 and they were all clean looking! And plus, isn't each earth going to also affect other systems if corroded/affected in any way?
The BCM must contain the relay. As most if us have never had reason to dismantle the BCM, and the actual component layout is not published, you will have to find it yourself.
The relay may well be what we'd see as a standard relay, or it may be smaller and a bit special for the BCM. Even so, it will be a mass-produced part, even if only supplied to control module manufacturers, so is likely to be available somewhere. Identification is the first issue.
If the relay is clicking well, either its internal contacts are not making contact properly, in which case it may be possible to clean them, or quite likely, there is just a connection issue within the BCM, fixable with a soldering iron and lots of care.
If this was mine, the BCM would now be on the bench, after probably lots of swearing during removal, with a view to locating the errant relay and its connection path.
The relay may well be what we'd see as a standard relay, or it may be smaller and a bit special for the BCM. Even so, it will be a mass-produced part, even if only supplied to control module manufacturers, so is likely to be available somewhere. Identification is the first issue.
If the relay is clicking well, either its internal contacts are not making contact properly, in which case it may be possible to clean them, or quite likely, there is just a connection issue within the BCM, fixable with a soldering iron and lots of care.
If this was mine, the BCM would now be on the bench, after probably lots of swearing during removal, with a view to locating the errant relay and its connection path.
:yeahthat:.
Just because you can hear the relay click, doesn't mean it's working properly; it only proves the relay solenoid is operating. You could still have a bad contact or a dry PCB connection.
Replacing the relay should be a straightforward enough job, providing:
- it's possible to disassemble the BCM without damaging it
- you can identify the failed relay
- you can source a replacement relay
- you have sufficient soldering skill to replace a surface mount relay without damaging the BCM PCB.
You won't be able to buy the relay from Fiat. Look for a part number or specification on the relay casing, and trawl the internet, starting with Farnell & RS components. It will only cost pennies.
If you succeed, you will have the satisfaction of having fixed something 99% of garages wouldn't even attempt. You'll also save a lot of money, since those 99% of garages would fix the problem by replacing the BCM.
Hard wiring the relays into the BCM is penny pinching design - a much better idea is to use plug-in socketed relays, which can be replaced much like the vacuum tubes in old radios.
I've repaired a failed Renault main beam circuit by doing something similar.
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According to the circuit diagram without the earth the wiper will not work.
High resistance will cause the motor to run slow.
According to the description the earth is in the passenger footwell.
However not sure if there is a difference between left and right hand drive.
all the other wires go to the body computer so if you follow the loom it should be the one that branches of and is bolted to the body
If you struggle I can look for you. Might be a while. Got to fix my brakes first.
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cannot mes show that wipers fail and reason why?
this would be my approach first
im thinking faulty bci though due to damp if the stalk is ruled out,is it ruled out??????????????? by substitution??????? as i lost the will after page 5
to summarise
change stalk with like for like if no mes
if fault still there consider body computer faulty......... not worth repairing.................... find same spec... or higher as suggested a lot earlier in thread by bill i think?............dont worry about mileage discrepancies and if it fixes your car fit drive and move on
these body computers/ ecu/ key should be really cheap now as these cars age ask before you buy from seller or us
this would be my approach first
im thinking faulty bci though due to damp if the stalk is ruled out,is it ruled out??????????????? by substitution??????? as i lost the will after page 5
to summarise
change stalk with like for like if no mes
if fault still there consider body computer faulty......... not worth repairing.................... find same spec... or higher as suggested a lot earlier in thread by bill i think?............dont worry about mileage discrepancies and if it fixes your car fit drive and move on
these body computers/ ecu/ key should be really cheap now as these cars age ask before you buy from seller or us
Replacing a relay in the body computer will be much easier and cheaper than sourcing and fitting a complete ECU/BCM/lockset.
If the OP is prepared to send me the BCM for a few days I'll happily look at the wiper relay in it FOC. Could just be a cracked joint on PCB. Some ABS modules are well known for this type of fault.
Robert G8RPI.
(professional electronics engineer, been repairing and designing electrical and electronic bits on aircraft, cars and other stuff for over 30 years)
