2003 XC70 intermittent “open tailgate” message, it is not th

321lor · Post by **321lor** » 05 Oct 2014, 11:31

Hi all,
I have been getting the intermittent “open tailgate” (2003 XC70) message for the last 6 months or so. It is fairly random and occasionally, the car alarm will also sound.
I have replaced the:
-switch inside the original tailgate latch- still intermittent “open tailgate” message
-the tailgate latch with another used one-still intermittent “open tailgate” message
-the wiring harness at the hinge with another used one still intermittent “open tailgate” message
Visually, there are no kinked or broken wires and all contacts seem to be fine.
Also, sometimes the “open tailgate” message clears when driving or when turning the engine off and on again.
It is not the tailgate latch or the wire harness!
If anybody with a more in depth knowledge of how the actual system works, could provide any suggestions what to look for this would be very much appreciated.
Thanks.

Post by **jimmy57** » 05 Oct 2014, 13:37

Remove tailgate inside trim around the glass and inspect elements there. There could be an element on the black area that has a connector that has come loose. I had a 2001 v70 that did this and that what it was. I think it is likely a way to nag you if you drive with a broken glass since the glass is structural.
I did not find any info on this on that car and I do not know if it is a feature of 2003 models. Since you have done exhaustive checks it is worth a look. Effectively they used this dedicated conductive strip (like the heating elements painted on glass) as the circuit path from latch or ground for the microswitch in latch.

321lor · Post by **321lor** » 05 Oct 2014, 13:53

Hi Jimmy57,
Many thanks for your suggestion.
Are you talking about the small wires heating elements embedded in the rear window?
When I replaced the wire harness I did have a look at the 3 metal connectors that go to the rear window heating elements and they seemed to be fine. Maybe I should look one more time with a flashlight.

Post by **jimmy57** » 05 Oct 2014, 15:00

It isn't the heater grid, or wasn't on the one I found. Check between ground and the three wires. Two should check nearly 0 ohms and the third will check as the resistance of the heater grid which is 2-4 ohms as I recall. My suspicion is the ground supply for the latch closed microswitch is via a unique conductor strip going to ground lead for glass heater strip.

321lor · Post by **321lor** » 05 Oct 2014, 16:27

Hi Jimmy57
Thanks.
Will get a new multimeter in about a week.
By the 3 wires, you mean the 3 metal connectors in which the tailgate wire harness is plugged?
Or there are other wires on the "black" portion of the rear window. Or are there 3 conductor strips in the "black" portion?
If I remember correctly nothing is easily visible there.

321lor · Post by **321lor** » 20 Oct 2014, 17:04

Anybody else with any suggestions.
It is a difficult one since it happens randomly.

hermechanic · Post by **hermechanic** » 21 Oct 2014, 09:07

I had the same issue with my '01 V70 a few years ago. Now I'm trying to remember what I found and did.
The latch switch grounding through the defogger grid sounds familiar. I think I just established a new ground - probably by way of the wiper motor. ~Steve

Post by **chrism** » 21 Oct 2014, 11:07

From what I have been able to glean from the wiring diagram...

http://www.volvowiringdiagrams.com/?dir=

...there is a pink wire that runs from terminal C:5 on the CEM, through disconnect 54/43 pin 11, (which is somewhere near the RH rear passenger seat) then through disconnect 54/78 pin 4 (which is probably the disconnect near the LH "D" pillar) to the tailgate latch micro switch (component 3/78). From the latch it is now a brown wire that runs through the glass breakage sensor (component 7/137) (wired in series with the micro switch), back through disconnect 54/78 again (pin 14) then to the ground point 31/47 that is somewhere near the REM on the LH side of the cargo compartment. It appears there are NO relays or fuses involved in the entire circuit from CEM to ground.

So if EITHER the latch micro switch OR the glass breakage sensor open, you will get a tailgate unlatched message.

The ground lug and both disconnects would be a good thing to check/clean. Also, it seems I recall reading that some people had an issue with the latch being out of adjustment that caused the micro switch to not open/close as it should. (Can you temporarily rig the micro switch in closed position or jump it just as a test? And lastly, heaven forbid, possibly an issue within the CEM???

321lor · Post by **321lor** » 21 Oct 2014, 16:08

Hello there,
Many thanks for your detailed reply and for looking at the wiring diagram.
I actually put a brand new latch micro switch on the latch but it did not make any difference.
Main problem it is very random, so it is difficult to pin point the reason.
I remember that one when I had the "tailgate open" message on I pushed the latch in close position but the message did not clear.
Will try this week end again one investigation to see if I can wiggle something to get the message.
Everything else in the tailgate (wiper, plate lights, etc. seem to work fine)
Question: can it be a bad relay in the REM (specifically the tailgate open or close one, I believe they are 18 or 19 in the REM schematic?)

Post by **chrism** » 21 Oct 2014, 18:15

From what I see in the wiring diagram, relay RMI19 only powers the lock/unlock motor in the latch. It has nothing to do with the latch/unlatch sensor switch.

You may have to ground the pink or brown wire at various points along their path in order to narrow down where the break actually is.

Maybe try jumping around the glass breakage sensor first to see if that helps. (I think someone has already hinted at that.)

Good luck.