Mg zt-t door-open warning light & rear wiper not working

[TonyPlymouth]

I'm a new member but have had my 53 plate MG ZT-T cdti auto (165k miles) for many many years. It is the family daily-used car, maintained and repaired on a DIY basis. The M-47 engine just keeps going and going and the JATCO auto box is as smooth as ever; no clutch to worry about but I had to put in a modified reverse piston a few years ago.. A great car and we are very fond of her.

Advice please from the gurus. Recently the door-open warning light has come on. Also the rear wiper stopped working about the same time. All doors and the tailgate and rear window lock and unlock normally using the remote fobs and door keys. The rear wiper arm is free to move by hand when the rear window is open.

Occasionally the latch has "chattered" a few times when opening the tailgate so I suspect the door-open light problem is here. Also I suspect the door-open and rear wiper problems are related.

In the absence of any wiring diagrams for the tailgate in the RAVE manual etc, could gurus comment on whether it is known that there is a link between the tailgate and/or rear glass latches and the rear wiper? It seems entirely possible that MGR designed the system so that operation of the rear wiper would be inhibited if the tail gate and/or the rear window were open.

If there is any doubt about this connection, perhaps a kind tourer owner would be prepared to do a little experiment and report back? The test would consist of checking whether the rear wiper works if the tailgate is open, and also if the tail gate is shut but the rear window open. Should take only a few moments.

Thank you in anticipation of any advice or report, and best wishes from Plymouth. Tony

[TonyPlymouth]

I should have also mentioned that whilst all doors and the tailgate lock and unlock normally, because of the door-open warning the alarm horn does beep momentarily when locking. Tony

[suzublu]

Originally Posted by TonyPlymouth

I should have also mentioned that whilst all doors and the tailgate lock and unlock normally, because of the door-open warning the alarm horn does beep momentarily when locking. Tony

I would check the bonnet switch, been known to cause the open light 😎

Sent from my moto g(7) power using Tapatalk

[TonyPlymouth]

Thanks suzublu for coming back with that tip. Much appreciated.

I should have reported in my initial post that I have already checked out the bonnet switch. It was a fiddly job but I found the wiring to be in good order, internally the switch is clean with no evidence of water ingress, and the microswitch inside is fully working. Using a strip of polythene sheet sandwiched between the bonnet and switch I was able to confirm the bonnet compresses the unit firmly and activates the microswitch.

Over this week-end I did a TOAF check which reported a "tailgate miss-lock" so my next move is to try a new (actually a second-hand one off eBay) tailgate latch in the hope this will cure both the lock issue and the rear wiper problem. Will report again when this has been fitted.

Tony

[trikey]

Before you buy anything, try separating the connectors that live behind the plastic trim at the top of the rear screen, these can suffer with corrosion and cause the mislocking issue.