Body Control Module

[Robmac]

I've had a problem with my wipers recently, the main problem being that they don't work! They move about an inch and then stop. At first I thought it would be at worst a new linkage and motor, or at best a strip down and refurbish so this is what I went for.

Having taken away the 2 cowlings which cover the mechanism, the problem was immediately apparent, the linkage arms were badly corroded and seized absolutely solid. My son (who is an engineer by trade) came around and reckoned it would be worth a go at refurbishing. We gave it a final attempt after spraying with WD40 but nothing was going to budge.

At that point, I noticed a whistling noise coming from the motor which was obviously still trying to turn the gears, so I switched off the wipers - the noise continued. I then switched off the vehicle ignition - the noise continued. I quickly unplugged the motor power supply and unbolted the mechanism. I then grabbed the motor as a handhold to pull the whole mechanism out - big mistake, the motor was red hot, and I mean hot.

We decided that the motor was continuing to run because the wipers were not in the 'home' position, however, quick test proved this not to be the case, so the power was being delivered either by a relay or the dreaded BCM. Searching around, there was no apparent relay for the wipers so the BCM had to be the problem. (My son had in the meantime checked that there was no problems with the wiper control stalk, but alas not that simple).

We located the BCM which is inside the large fusebox in the engine compartment (annoyingly you have to remove the radiator header tank to get at it but no big deal) , somewhat annoyingly, the 30amp wiper fuse had signs of wear and excessive heat, but had not blown which possibly would have saved the BCM.

Looking on Ebay, I found a brand new Renault supplied (apparently) Linkage and motor (I decided to replace the motor as although it was still working it had been subjected to some extreme heat). The part was £250 compared to £428 supplied directly from our local Renault dealer. I also found a BCM for £50 from Ebay, I didn't even ask for a price from Renault as I believe they run to several hundred pounds. I will also have to pay £75 for reprogramming (cloning) of the BCM unless I can find a cheaper way.

When the parts arrive next week, I shall continue the thread and post some photo's. The vehicle is a 2012 renault Master 2.3 DCI.

Who would have thought that fixing dodgy wipers would be so complicated/expensive?

That's progress I suppose.

(Constructive criticism welcomed, I am definitely not a mechanic or auto electrician!)

 

[autorouter]

We decided that the motor was continuing to run because the wipers were not in the 'home' position, however, quick test proved this not to be the case, so the power was being delivered either by a relay or the dreaded BCM.

I've not worked on wipers for some years, but I thought there were two power wires to a wiper - one from the switch, and one either permanently from the battery or from the ignition. If the internal switch that turns off the power in the home position is faulty and shorted, or the mechanism that trips the switch is jammed/broken, then the power will continue to flow

 

[hilldweller]

That's progress I suppose.

Oh yes. Oh YES. The wonderful progress.

A wiper control needs two wires, a limit switch an on/off switch and a ground.

So, enter the genius from Uni, I can improve this, just throw in a few hundred thousand transistors, a hall effect sensor and I can change those two massive copper wires to one thick one and one thin pair and give proper control to the wiping.

And you are now paying the price of his education.

 

[Robmac]

I've not worked on wipers for some years, but I thought there were two power wires to a wiper - one from the switch, and one either permanently from the battery or from the ignition. If the internal switch that turns off the power in the home position is faulty and shorted, or the mechanism that trips the switch is jammed/broken, then the power will continue to flow

I'm pretty sure my son tested for this. The only way to stop the wiper was to disconnect the BCM.

I will double check though, thanks.

 

[Robmac]

Great service from the suppliers. The linkage arrived yesterday afternoon, less than 24 hours after I ordered it.

Unfortunately it is broken! The ally castings on both ends which house the splines are broken, there is probably enough left to grip the splines and do the job, but I'm not happy to do that with an item which cost £250.

Looking at the box it came in, there are indentations on the inside of the cardboard where the castings were pressed up against the ends of the box, so it looks like it has probably been chucked about by the couriers.

I hope this isn't going to be the start of a long ebay dispute!

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[Robmac]

The new BCM (well second hand really!) has now arrived and I have tested it on the old motor and it does indeed now switch off once the home position is reached.

Next step is to send off my old BCM along with the new one to have it cloned so all of the settings for the rest of the functions and the imobiliser are the same and all should be good.

 

[Figaro]

I hope this isn't going to be the start of a long ebay dispute!

Very unlikely, eBay are most definitely on your side and will make sure it's resolved, if necessary doing the refund themselves and deducting the money from the seller if they don't deal with the dispute.

 

[Robmac]

Very unlikely, eBay are most definitely on your side and will make sure it's resolved, if necessary doing the refund themselves and deducting the money from the seller if they don't deal with the dispute.

Yes, I am in the middle of a dispute at the moment. The seller sent the wrong item and then claims she sent a replacement. She keeps on sending me the details of the first tracked delivery insisting that this is in fact the delivery of the replacement, despite the fact that the tracking details state that the package was delivered on the 30th June. This is the day BEFORE I emailed her to say that she had sent the wrong item!

 

[Figaro]

I can only say my experience of eBay disputes is they make sure they are quickly resolved but I suppose there's always an exception

 

[Robmac]

I can only say my experience of eBay disputes is they make sure they are quickly resolved but I suppose there's always an exception

I was wrong to doubt this dealer, he issued a refund without question once the part was returned and I have now reordered from him so I shall carry on the thread once the new part arrives.

I have also just been informed that I have won the dispute I had outstanding so my faith in ebay is restored!

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[Robmac]

Further confusion now!

I have tried the new (second hand) BCM in the van to check the wipers work properly and they now do. What is confusing me though is that everything else works too and the van starts which it shouldn't without the new BCM being cloned to the old one.

I 'phoned the 'cloners' and they asked for a part number for the BCM. Having given them this, they looked it up and informed me that this is not the BCM but a fuse box. (It was advertised as a bcm and although it does have a fuse board on it there is also a black compartment behind the board which I had assumed was the circuitry for the BCM).

I suppose there could be relays in the black box, I will dissect it when the new wiper linkage arrives and everything is proven to be working on the new 'box'.

 

[Robmac]

New linkage now fitted as is the new fuse board and all is working as it should.

Total cost about £300 and the van has now gone in for it's MOT so fingers crossed.

Thanks for your input everybody.