Tailgate Microswitch Adjustment?

[John Underhill]

I've been getting a few random alarm siren activations over the last few days, but I have already replaced the alarm module about 18 months ago, so I don't suspect that it will have failed again yet!

I have also noticed an occasional "tailgate open" DIM amber warning when in fact the tailgate is firmly shut, which I think could be the root cause of the alarm problem.

Today I noticed a very intermittent "tailgate open" message after driving over a bump and the tailgate interior light was also flashing in time with the DIM message. This all settled down and disappeared after a couple of miles.

Obviously there is a loose connection activated by vehicle movement and since the interior light is triggered at the same time I'm assuming it's related to the micro switch circuit.

I did have to lean on hard and slam the tailgate a while ago to squeeze in a protruding load which possibly may have impacted on the locking mechanism?

Is there any adjustment for the micro-switch activation, if so, how?

Or, should my first port of call be the hinge?

Grateful for any advice please!

Cheers

John

[Chris_Rogers]

The fixed portion of the lock on the body work is adjustable, but if the tailgate is firmly closed then I can't see this altering the microswitch operation.

I'd go for the hinge, is anything else in the tailgate not working, rear wiper, screen heater?

[Missing Lincs]

As above but to the part about the fixed part of the lock ie the striking plate being adjustable, it also moves side to side. Check that the tailgate is centred in the opening when closed. Mine wasn't and as result the second part of the latch action when closing wasn't quite going far enough which give intermittent tailgate open messages.

[John Underhill]

Thanks Guys

All tailgate electrical functions are working.

I hadn't spotted the 2 plastic blanks on the tailgate bottom rim that allow access to the striker plate before and as you say there is a degree of adjustment, both lateral and fore and aft, available.

Having marked the original position, I have moved the striker plate rearwards a mm or so, which might have solved the problem. I've opened and closed the tailgate several times now and have been unable to replicate the "tailgate open" message other than if the tailgate is on half-****.

I've put the car back on alarm so I guess it's wait and see!

[october37]

I have a similar problem, but my tailgate functions ok except for the "Tailgate Open" warning and failure of the cargo area light when the tailgate is open. I have checked the wireing to no avail but notice that one of the black plastic guide blocks is missing from the lock striker plate in the tailgate floor. Given your post, could this be the cause of my problem?


Keith 55reg V70se 2.4 Auto

[John Underhill]

Thought it was too good to be true!

Alarm is sounding again

No "tailgate open" warning!

I guess it's back to the drawing board for another solution

[Simon Jones]

Unless you really need the tail gate warning feature, I'd be tempted to trace the wiring in the boot area and short the two wires together so it's always off. I had to do similar temporary thing on my last V70 as it had the classic passenger door microswitch failure that meant the door would not stay locked and the interior light would come on while travelling along. Replaced the lock unit and restored the wiring.

EDIT: just re-read your post and it sounds like your switch is ok now at least.

[100K+]

I have had a similar issue - hitting bumps and tailgate open warning/boot light coming on. Traced mine to the earth of the rear window breakage sensor.
Its on the same circuit as the micro switch but the blasted wires change colour, so its not straight forward unless you have the tailgate trim off.
My solution was to scotch clip an earth to the same wire as fed the window sensor - problem solved.

See my post here http://www.volvoforums.org.uk/showth...ighlight=earth

Hope this helps
Cheers

Bob

[Jetmech]

Check the wiring where is passes around the left tailgate hinge, I had similar issues and found several broken wires in this area. http://www.volvoforums.org.uk/showthread.php?t=183861

[John Underhill]

Well,I've finally got round to having another look at this issue since the "tailgate open" warning became on all the time!

The Microswitch was working OK and there were no obvious breaks in the loom at the hinge, but I continuity checked the pink wire from tailgate lock connector to the hinge loom and that was OK. The other Microswitch wire is brown but does not go through the hinge loom! I eventually found a brown wire leading to a tag at the edge of the rear screen, just below the heated rear window positive tag. There was continuity from the Microswitch brown wire to this tag which I presume is a broken glass sensor? This tag was not earthed or powered and I couldn't find a corresponding second tag anywhere round the window to complete a circuit!

I took a chance and routed the window brown wire tag to earth by splicing it to the adjacent rear screen heater thick black wire with scotch lock connectors. Everything is now back to normal and the alarm has been set for several hours without issue.

Can I assume that the brown wire window tag is the broken glass sensor which is faulty? I am assuming it is normally earthed through the heater element and alarms if the earth route is broken.

Grateful for confirmation of my thoughts and suitability of fix or otherwise please!

Cheers

John