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| dorsetsmith Member Since: 30 Oct 2011 Location: South West Posts: 4554  |
 Click image to enlarge Courtesy light are operated by the alarm unit this unit will still be in place even if you have no key fob just not enable with all its function. the door switches provide switched ground input to the alarm unit and it provide switched ground to the Courtesy light all the door switches to (A) but one i.e. drivers door switch to (B) Last edited by dorsetsmith on 29th Oct 2020 10:30am. Edited 6 times in total |
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29th Oct 2020 7:06am |
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| V8GPC Member Since: 18 Jul 2016 Location: Manchester Posts: 289 
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i found on mine it was the screws that fit the switches that had a little corrosion, and not making the contact. I replaced both switches and also fitted new screws. This fixed the problem.
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29th Oct 2020 7:10am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17344 
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It's really not that unusual! The door switches simply switch to ground so are easy to to test - take the feed wire off the switch and connect it reliably to a ground and see if the light comes on. As V8GPC says, corrosion of the switch screw (which provides the ground connection) is a very common problem. |
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29th Oct 2020 8:57am |
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| peanutbob Member Since: 12 Feb 2009 Location: UK Posts: 289
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Thanks for the replies. We have taken off both switches, cleaned them up and tested the incoming voltage which is 11.v on both sides.
I wonder if on 09 plate hard tops in basic trim I.e. non county, if an alarm was a standard fit... I guess so, especially as there is an interior movement sensor block factory fitted. Maybe the alarm has been deactivated in the past but still providing the earth . I’ll go over and check in the meantime but 2 new switches cost £11.00 delivered so I might as well order these especially as one switch is bent. If it has got a non functioning alarm then one would have to alter how the switch is earthed via this. Also will take the wire off and connect to ground. |
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29th Oct 2020 9:11am |
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| Martin Site Admin Member Since: 02 Apr 2007 Location: Hook Norton Posts: 6604 
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The voltage you are seeing on the wires is correct, they are "pulled up" the alarm unit to battery voltage, and grounded when you open the door - the alarm unit detects the drop to 0V as a door open.
The ground path is via the fixing screw, so make sure the screw is clean as well when you fit the new switches. Touching the female connector for the switch onto a ground point (e.g. a screw back in the switch fixing hole) should trigger the alarm unit to bring on the interior light. Make sure the light itself is in the "auto" position, there are 3 positions = ON, OFF and AUTO. Central locking/alarm might not be enabled on but ALL Pumas have an alarm unit/ECU fitted to provide the immobiliser signal for the engine ECU, and it controls the interior lights from the door switches. The door switches aren't directly connected to the interior lamp, they haven't been since the immobiliser equipped 300 Tdis and then all Td5s. Not sure where you have seen that if the alarm unit is fitted but non functional as an alarm means the switches don't work, or that they need wiring differently? 1988 90 Td5 NAS soft top
2015 D90 XS SW |
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29th Oct 2020 10:33am |
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| peanutbob Member Since: 12 Feb 2009 Location: UK Posts: 289
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Hi Martin
Understood and thanks. I’ll check tomorrow when I go over to his house. Reading a variety of threads ref the switches, I thought that the alarm provided the earth, so that if the door switches are not faulty then the issue might be relating to the alarm/immobiliser. The interior sensor is in place behind the driver, which makes me think that there used to be an alarm (unless the sensor is always fitted anyway whether or not there is an alarm) and it’s been disconnected. |
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29th Oct 2020 10:47am |
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| peanutbob Member Since: 12 Feb 2009 Location: UK Posts: 289
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I’ve taken the spade connector of one of the switches and grounded it in several places inc the self tapper on the switch but light still not coming on even though there is a live feed. I guess the problem must be allied to the alarm/ immobiliser.
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30th Oct 2020 1:14pm |
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| Martin Site Admin Member Since: 02 Apr 2007 Location: Hook Norton Posts: 6604
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Is the roof light switch in the AUTO position? Just want to doubly make sure you've not pushed it over to "OFF".
1988 90 Td5 NAS soft top
2015 D90 XS SW |
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30th Oct 2020 1:19pm |
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| peanutbob Member Since: 12 Feb 2009 Location: UK Posts: 289
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100pc auto!!
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30th Oct 2020 1:24pm |
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| Martin Site Admin Member Since: 02 Apr 2007 Location: Hook Norton Posts: 6604
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The switches are clearly connected to the alarm unit (as you can detect 12V on them), so it could well be that the alarm unit is configured to not operate the interior light. Without a diagnostic tool on it you can't tell though. Or the wire out from the alarm to the light is broken so although it is trying to switch it on the signal isn't getting through. 1988 90 Td5 NAS soft top
2015 D90 XS SW |
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30th Oct 2020 1:35pm |
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| peanutbob Member Since: 12 Feb 2009 Location: UK Posts: 289
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It’s had a replacement rear door at some stage and there’s no switch on this nor any evidence of wiring plus the drivers side switch is bent and possibly shot...but I don’t think the switches are wired like Xmas tree lights so that if one fails then they all do not work.
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30th Oct 2020 1:36pm |
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| Martin Site Admin Member Since: 02 Apr 2007 Location: Hook Norton Posts: 6604
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Correct, they are in parallel (driver's door is on its own wire)
1988 90 Td5 NAS soft top
2015 D90 XS SW |
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30th Oct 2020 1:48pm |
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