Central Locking Issues

[darbon]

Hi there, a newbie to the Group and this is my first post and it’s to do with a problem on the central locking. I've had a look around the forum already regarding the problem and have tried out a couple of things without success (wiring loom in boot, door mechanism by removing card, etc). My past trade was Electronics Engineer so have a good understanding of electrics etc and I wield a mean soldering iron!!

Recently bought a 2005 ZR105 Trophy SE and everything has been fine up until a couple of days when I went to car and found the central locking from the fob wasn’t working. Changed the batteries in both fobs with CR2032s and made no difference to the following fault with either fob:
Pressed unlock on the fob and had the flashing indicators but no noise of the doors actually unlocking. Went to open the door with the handle but drivers door wouldn’t budge. Pressed the lock function and heard the drivers door lock and 3 flashes on the indicators. Pressed unlock again and just the flashing – no sounds.

Pressed Boot Open function and heard click and that opens with no problem. Pressed lock and had the alarm beep once indicating door open. Closed boot and pressed lock and still no sounds. Pressed unlock and opened drivers door with the key and started the engine OK. Stopped engine, got out of car and pressed lock – sounds heard and door pin receded down and locked. Pressed unlock and nothing except indicator flash. Opened driver door with key again and the passenger door will not open at all – lifted pin but little or no movement and won’t open either internally or externally.

Have checked the wiring as far as I can without removing the connection in the tailgate and pulling the cable through and all the wires are clean and solid with no breaks in the insulation. Also had a look at Fuse 5 in the engine compartment and that OK as well – visually and continuity checks done.

At a loss now as to what else it may be so looking for some pointers on what to check next please? Any advice gratefully received.

Dave

[rakester]

Sounds like it could be issues with the SCU, it is common for water to get into them on the MK2.

Give Remobile a PM on here, he is a specialist in this stuff and can most likely fix it for you.

[Remobilise]

Dave - Probable cause is the Relay in the Pektron unit. Not unlocking. Locking OK.

Two relays live in the one black box -and there is five of those..one locks and one unlocks.

Try resetting by removing the battery neg and leave it for five minutes then connect up again.

It may lock OK then go back to NOT locking afterwards...
You need to remove the unit (behind the glove compartment) can send removal instructions etc and pics..open it up and check the relay - its the one on the right in this picture.
Pektron Relay ID 3 (Medium).jpg

You can test it in situ - just connect up the connectors and the neg battery terminal (you took off BEFORE you removed the unit ) and with your finger on that relay you will tell for sure if its working. Although sometimes if the points are well corroded current may and may not always flow - even though the relay latches. So a intermittent fault develops.

We can supply the relays as per the picture below.
I would recommend changing all five as you will find one goes then another months or so later. It a multilayer board with through hole soldering required but that should be bread and butter to you sir..

Pektron Board & Fujitsu Relays.jpg

Should also say as Jake pointed out that the mark II has the Pektron inverted like the mark one and water tracks down the cables into the connectors and into the SCU Pektron unit causing interesting results. If and when your replace it put it back the 'wrong' way up so that the connectors feed in from below - you will find enough room to do this.

[darbon]

Thanks for the quick replies guys - will have a look over the weekend at the SCU (which I understand can be a bit of a bugger to get too!!) and let you know. As a matter of interest, how much for the whole relay set, just in case??

[Remobilise]

For you to do the job - 5 New relays delivered to you £30.00 inc postage. (signed for)
If you were a fully fledged member on here then its £25.00 inc postage. (signed for)

Full members will save a fair bit Darbon, thats one of the benefits of clicking here

For us to do the job £70.00 including the relays plus postage (special delivery -signed for- because of the replacement value if lost or missing etc-free insurance by Post Office to £500)

PS if you want removal pics and location info will be happy to email them to you. PM me your email. If you have AirCon its then interesting.

Kev

[Cnrcol]

Can you help...I have a 2004 mgzr 160, I left it standing for four weeks and the battery was flat. Key fob wouldn't open the doors and the alarm obviously didn't work. I charged the battery and then tried to start the car. It would start for three seconds then the immobiliser shut it off. I have managed to get the key fob to turn off the immobiliser and the car will start, but now the fob won't open or lock the car using the buttons?? Also if I lock it manually the doors don't all lock automatically. Plus the door lock on the dash doesn't work. All of this worked fine before the battery went flat .???? What can I do?

[Happax]

Yeah mine did the exact same thing after leaving the car with the windows open and the car off for over a month, (sitting in the workshop, engine in bits). We quickly figured it was to do with the BCU (SCU) as all the interior/alarms etc were playing up. I then got a heat gun set to low and aimed it at the BCU and after about half an hour all was well again. This is (as mentioned above) because the BCUs are prone to water ingress so the heat gun dried it all out in this case, but if the water is left there too long corrosion will occur and drying it out is unlikely to do much. Also this may not be a permanent fix as more water could seep in later on, but touch wood I haven't had any more problems.

[Aldo]

We had our windscreen replaced and they did a bad job. Long and short of it is they re-replaced it, but before they did, there was a major rainstorm and it got soaked inside.
Central locking was a bit intermittent after that. Then eventually the passengers door wouldn't unlock.

Thanks to this forum I got to the bottom of it.

What i did:
I used this video to locate and remove the unit:
https://www.youtube.com/watch?v=sQeFa5v5DXM (hope links are allowed, if not, sorry).
Then using the picture above telling which relays did what. I removed the washer relay (washers worked fine)and the central locking relay. Then put the washer relay in the central locking space. All locking mechanisms are now working.

So thank you people. This is what makes the interweb so great