The Dispatch | Expert | Scudo Hub

RegW

Member

From: Bristol

Registered: 2024-04-21

Posts: 334

Central locking testing

The central locking was only working on both the front doors and the near side sliding
door.
I looked at the rear door and found both wires had broken off I think due the lining
that had been fitted had been crushing them in the tube when the door was closed

I lashed up some flying leads to test for function and it worked fine
so laid in new 2 core cable through the tube, made connections and that's now working.
I haven't looked at the OS door yet but did test for power at the door frame contacts
and got inverting power so the problem is on the door.
I saw some evidence of previous lash ups which I corrected while I was at it

fault finding testing is straight forward with a meter
There is a common Orange and Violet (purple) wire to each lock motor
powered by something like an H bridge affair which flips polarity
from lock to unlock.
When locking, the Orange will go positive and the Violet negative
in relation to each other, Unlocking gets the reverse

Unless you have a sample and hold meter, this will happen too fast for your meter to display or you to see but holding probes on the contacts and pressing the fob buttons, my meter did tell me when it had detected a positive or negative voltage so that was all I needed to know for my cursory tests.

---

When all else fails, RTFM  - 2006 Expert 2.0 HDI/110

Oscarklemo

Member

From: Sweden

Registered: 2025-04-30

Posts: 57

Re: Central locking testing

Where is this "H bridge affair" to be found? Is it in the lock?

Do you know where the control box is situated?

---

1998 Citroen Jumpy 1.9TD XUD9 TE

RegW

Member

From: Bristol

Registered: 2024-04-21

Posts: 334

Re: Central locking testing

An H bridge is basically/usually a control ciruit that can flip the polarity
pos/neg to neg/pos making say, a motor run in either direction.

I'm only assuming an H bridge, but it may just use relays instead.
Sorry, I have no idea where the controller is, all the locks on my van have just the two wires
going to them and the controller is buried under the dash or in the engine bay for all I know.
I haven't had to search the thing out yet.

Last edited by RegW (2025-06-29 23:47:03)

---

When all else fails, RTFM  - 2006 Expert 2.0 HDI/110

Oscarklemo

Member

From: Sweden

Registered: 2025-04-30

Posts: 57

Re: Central locking testing

I found an aftermarket remote central locking unit which I am thinking of fitting.

This one, (subtitles in english)

I read in the comments of the product that some people experienced only being able to use one button, for locking and unlucking.

Also, I've read on this forum that the dispatch/jumpy/scudo/expert uses just one polarity for locking/unlocking i.e. 12v on or off.

---

1998 Citroen Jumpy 1.9TD XUD9 TE