Member Since: 31 Aug 2010
Location: retford'ish
Posts: 2210
UpDated. The Volts at upper tailgate switch should be 12V
Hi,
have been busy reading upper tailgate threads
and now have a some checks to do as I have cut the micro switch off ready for a replacement
but
its not a switch fault as when I touch both wires together Nothing happens so switch was ok
so
To test the wires what Voltage should I have on 1 wire
some threads mention 12V and some Permanent 6.5V
looking at Gary's pic should the other wire from the switch go to an Earth, if it does can I put in my own earth to see if the actuator then works ?
If I understand correctly the upper tailgate switch goes to earth when pressed which the FET see's and sends a pulse to operate the actuator in the lower tailgate
Last edited by riverblanche on 3rd Jan 2023 6:49 pm. Edited 1 time in total
30th Dec 2022 10:32 pm
Leon
Member Since: 26 Apr 2014
Location: Leamington Spa
Posts: 429
Hi,
The way I think it works is 6.5 volt on one side of the switch (from the FET) and the other side to earth so when the switch operates it drops the 6.5v to earth.
The CJB then sends 12v to the actuator
So in thery you can put the 6.5v wire to earth, this will check your earth wire.
Take it you have 6.5v?
Regarding your question in the other thread my broken wire was in the loom in the tailgate handle.
Since yours is the same fault as mine was -opens on the dash buttons I would look for a broken wire in the loom at the back. Wished now I had taken some more voltage readings after finding the broken wire but I was so pleased I found the fault I just repaired it and put it back together.
31st Dec 2022 9:37 am
riverblanche
Member Since: 31 Aug 2010
Location: retford'ish
Posts: 2210
Thanks Leon,
thats why I was unsure what the Voltage should be and if you checked it after your fix, was it still the 6.5V, as seen couple other threads mention 12V
more checks today and before unlocking the D3 on 1 wire I had 8.7V but this dropped 0.2V every second,
just like it was counting down
took multimeter off at just under 7V and unlocked the D3
earthed the live cable to see if actuator worked........ No
multimeter back on and volts still dropping 0-1-0.2V got down to 4.8V then stabilised at that.
I'm confused
suspect fault in wire coming to the switch but what should it do and what Volts should it be when its working correctly
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20732
99% sure its 12v. Switch completes the circuit when pressed
There is a connector under the passenger seat, with 4 terminals. Unplug it, and check the side from the BCM, and check for voltage there My D3 Build Thread
Member Since: 20 Jul 2015
Location: Here
Posts: 575
Agree - 6.5V is not a usual voltage for a switch circuit, neither is dropping voltage which indicates a capacitive/resistive (i.e. damp or corrosion) fault. Sensor circuits operate between 0.2-4.8V, switching circuits operate at battery voltage (nominally 12V). Check voltage at the corresponding wire connector above the headlining at the tailgate - also check the ground connection at the same location.
31st Dec 2022 9:49 pm
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20732
Alcohol has helped my memory
Take the handle off, and check the wiring inside. I've seen quite a few break in there. Easy enough to repair once you have access My D3 Build Thread
Member Since: 26 Apr 2014
Location: Leamington Spa
Posts: 429
With all them funny voltage readings I would as mikey says be looking for a broken wire in the handle loom, mine wasn't obvious the insulation was still intact on the outside of the boken conductor.
Go along all the wires 1/2 inch gap between fingers and give a tug.
Mine was 10mm out front the protective cover that hold all the wires together.
Sorry I didn't check voltages after the repair.
1st Jan 2023 11:00 am
riverblanche
Member Since: 31 Aug 2010
Location: retford'ish
Posts: 2210
Thanks for the replies All,
will investigate over the next few days and update the thread with what I find
Member Since: 31 Aug 2010
Location: retford'ish
Posts: 2210
Hi,
it stopped raining so had a look this afternoon, it seems someone has been in here before
Two of the four Torx bolts (circled in red) decided instead of unscrewing from the captive part in the handle they would un-screw the captive part from the handle, I thought they had sheared
but no and they have gone back in fine
I split the multiplug inside the top tailgate (yellow is to handle switch and red is feed plug) and tested supply here (next step would have been Mikey's under seat suggestion )
12V on top right pin and when earthed the actuator worked
(close up pic of multiplug in my D3 gallery)
so fault from here to switch and as said it was a corroded wire break,
thanks Leon mine was about 70mm from the switch where the tape/sleeve meet not really a flex point but maybe damp got in.
New wire soldered in and extended
Still got to get a new switch but everything is now back together and working fine when you touch both wires together
I have programmed the 3rd button on my remote and taped the wires up until new switch sorted.
Confirmation the switch should have 12V to it,
as Flatlander also said fluctuating and 6.5V suggested corroded wire, it was.
Member Since: 20 Jul 2015
Location: Here
Posts: 575
Well done! I did think about testing at that connector but suggested the one by the hinges as it's easier to get to. I've never known the brass inserts to not unscrew themselves from the handle assy...
3rd Jan 2023 7:23 pm
Leon
Member Since: 26 Apr 2014
Location: Leamington Spa
Posts: 429
Well done!, sounds like the corrosion was in the same place as mine, wonder if they are nicking the cable when assembling the loom, mine had the tiniest bit of green corrosion on the outer insulation that when pulled the wire came apart. Good to know about the 12v as I said before I didn't measure the voltage after I repaired it.
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