Green200tdi Posted August 30, 2023 Share Posted August 30, 2023 Have a td5 loom in my 1986 110 most of its up n running but the interior light is only working in the ON possession, when I earth out the door switch wire and have the light switch to the middle there’s nothing any ideas 💡 Quote Link to comment Share on other sites More sharing options...
Wytze Posted August 30, 2023 Share Posted August 30, 2023 Is the bulkhead earthed? It looks all nice and painted. Quote Link to comment Share on other sites More sharing options...
Green200tdi Posted August 30, 2023 Author Share Posted August 30, 2023 43 minutes ago, Wytze said: Is the bulkhead earthed? It looks all nice and painted. Yes I put a electrical tester from the positive of the battery to the bolt the light come on Quote Link to comment Share on other sites More sharing options...
Wytze Posted August 31, 2023 Share Posted August 31, 2023 7 hours ago, Green200tdi said: Yes I put a electrical tester from the positive of the battery to the bolt the light come on And there is 12volt on the wire going to the door switch? Quote Link to comment Share on other sites More sharing options...
Peaklander Posted August 31, 2023 Share Posted August 31, 2023 The PU cable to the door switch is a 0V path for the lamp, not +12V. In DOOR position on the lamp, the door switch provides a path to body (0V), in the same way that the lamp has a direct path to 0V (local to lamp), when the switch is in the ON position. So I would say that the door switch locating screw is not connected to body. You should check for continuity from the that screw to battery -VE. Edit (This all presumes that you haven't fitted a 10AS alarm unit) 1 Quote Link to comment Share on other sites More sharing options...
Crashbanggg Posted August 31, 2023 Share Posted August 31, 2023 My interior light was working very intermittently (/poorly), I stripped the light unit itself down and found a lot of corrosion on the switch contacts. Cleaned all that off and now working as it should. (...though perhaps not the case if it was working with the previous loom) Quote Link to comment Share on other sites More sharing options...
Wytze Posted August 31, 2023 Share Posted August 31, 2023 (edited) 50 minutes ago, Peaklander said: The PU cable to the door switch is a 0V path for the lamp, not +12V. In DOOR position on the lamp, the door switch provides a path to body (0V), in the same way that the lamp has a direct path to 0V (local to lamp), when the switch is in the ON position. So I would say that the door switch locating screw is not connected to body. You should check for continuity from the that screw to battery -VE. Edit (This all presumes that you haven't fitted a 10AS alarm unit) Then you should see 12 volt on the multimeter between the PU and earth, yes? Or do i need more coffee? 😁 After a second cup... Yes, 0 volt😂 The rusted terminals , sound like a plan Edited August 31, 2023 by Wytze Duhh Quote Link to comment Share on other sites More sharing options...
Peaklander Posted August 31, 2023 Share Posted August 31, 2023 26 minutes ago, Wytze said: Then you should see 12 volt on the multimeter between the PU and earth, yes? Or do i need more coffee? 😁 No, the switch is on the 0V side of the lamp bulb. More coffee in the morning is always a good thing. 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 31, 2023 Share Posted August 31, 2023 You should still see 12V between the wire and earth, it will drop to 0 once connected to earth, as the voltage drop will then be across the bulb. If you don't have 12V then suspect the switch as above. Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 31, 2023 Share Posted August 31, 2023 As I recall, there are three terminals on the back of the lamps. One is clearly direct to earth. The others are for the live feed and the door switch (earth ). Are you certain you have the right polarity? You could have the feed on the earth side and the earth on the feed side. That might not just prevent the door switches from working, but might also be a short circuit if my memory of their construction is correct. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted August 31, 2023 Share Posted August 31, 2023 1 hour ago, Bowie69 said: You should still see 12V between the wire and earth, it will drop to 0 once connected to earth, as the voltage drop will then be across the bulb. I was going to say this and then thought not. I know that no current flow means no voltage drop and so +12V will be there. Also multimeters have very high impedance so don't load the circuit but I don't think I have tried to see if the floating +12V is actually measurable. Obviously it is. 😀 Quote Link to comment Share on other sites More sharing options...
PaulMc Posted August 31, 2023 Share Posted August 31, 2023 The TD5 interior light(s) are controlled by the 10AS unit. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted August 31, 2023 Share Posted August 31, 2023 2 hours ago, PaulMc said: The TD5 interior light(s) are controlled by the 10AS unit Yes and if that unit has been fitted, the door switches are cabled back to it and there is a control cable from the 10AS up to the lamp. That means there are three wires going to the lamp; +12V IGN, 10AS controlled 0V and permanent 0V. The 10AS can then control the interior light when the switch in in DOOR. However it won't do anything after a door has been left open for >15 mins, unless the Driver's door is closed. This resets the timer. Quote Link to comment Share on other sites More sharing options...
Green200tdi Posted August 31, 2023 Author Share Posted August 31, 2023 9 hours ago, Wytze said: And there is 12volt on the wire going to the door switch? Isn’t the door plunger just an earth? to light the light 💡 Quote Link to comment Share on other sites More sharing options...
Green200tdi Posted August 31, 2023 Author Share Posted August 31, 2023 9 hours ago, Peaklander said: The PU cable to the door switch is a 0V path for the lamp, not +12V. In DOOR position on the lamp, the door switch provides a path to body (0V), in the same way that the lamp has a direct path to 0V (local to lamp), when the switch is in the ON position. So I would say that the door switch locating screw is not connected to body. You should check for continuity from the that screw to battery -VE. Edit (This all presumes that you haven't fitted a 10AS alarm unit) 😂😂😂😂😂😂😂 sorry, are you saying the door plungers at just an earth??? no switches as I have this wire stright to earth on battery Quote Link to comment Share on other sites More sharing options...
Green200tdi Posted August 31, 2023 Author Share Posted August 31, 2023 3 hours ago, Peaklander said: Yes and if that unit has been fitted, the door switches are cabled back to it and there is a control cable from the 10AS up to the lamp. That means there are three wires going to the lamp; +12V IGN, 10AS controlled 0V and permanent 0V. The 10AS can then control the interior light when the switch in in DOOR. However it won't do anything after a door has been left open for >15 mins, unless the Driver's door is closed. This resets the timer. I have no 10 AS connected would that make a difference? Quote Link to comment Share on other sites More sharing options...
PaulMc Posted August 31, 2023 Share Posted August 31, 2023 2 minutes ago, Green200tdi said: I have no 10 AS connected would that make a difference? Yep! You'll have to modify the wiring to make the door switches switch the interior lights to earth. Not too difficult, I'll see if I can dig-out a diagram. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted August 31, 2023 Share Posted August 31, 2023 15 minutes ago, PaulMc said: Not too difficult, I'll see if I can dig-out a diagram There’s the diagram I posted earlier. Quote Link to comment Share on other sites More sharing options...
PaulMc Posted August 31, 2023 Share Posted August 31, 2023 25 minutes ago, Peaklander said: There’s the diagram I posted earlier. The TD5 with the 10AS is slightly different - To do away with the 10AS functionality, and revert to door-switched interior lights, you need to connect the following wires together - PW (C0061-1), SW (C0061-5), and PU (C0061-16) You can do this by cutting and splicing the wires at the Grey 10AS connector (C0061) (rear of connector) If you wanted to keep the loom's integrity (for fitting a 10AS in future), I could make-up a plug-in to connect terminals 1, 5 and 16 together. . 1 1 Quote Link to comment Share on other sites More sharing options...
Green200tdi Posted August 31, 2023 Author Share Posted August 31, 2023 1 hour ago, PaulMc said: Yep! You'll have to modify the wiring to make the door switches switch the interior lights to earth. Not too difficult, I'll see if I can dig-out a diagram. I do have an 10AS no idea wher it is 😂 thanks 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 31, 2023 Share Posted August 31, 2023 I am more confused about this than the £200K website I've been building today. 1 Quote Link to comment Share on other sites More sharing options...
Peaklander Posted August 31, 2023 Share Posted August 31, 2023 @Green200tdi you have said it’s a 1986 110 but has a TD5 loom. Are you or have you ‘fitted’ the loom? You appear to be sending this thread around the houses. Quote Link to comment Share on other sites More sharing options...
western Posted August 31, 2023 Share Posted August 31, 2023 He has fitted the td5 loom, the door switches are earth for the interior light, I have the interior light in my 110 & it's wired to operate off the dash switch & the switch in the light unit, Quote Link to comment Share on other sites More sharing options...
Peaklander Posted August 31, 2023 Share Posted August 31, 2023 The pre-10AS wiring is easy and shown in the diagram I posted this morning. If that's what he is aiming for then it shouldn't take too much debugging. If there is a 10AS unit fitted, as the OP suggests but the wiring isn't correct, or partly mixed with the 10AS method, then it will be confusing. I have explained how it functions and where the wires connect and @PaulMc has as usual, provided a wiring diagram and also an elegant solution to bypass the 10AS, if that is what is required. I think I'll wait and see.. 1 Quote Link to comment Share on other sites More sharing options...
Green200tdi Posted August 31, 2023 Author Share Posted August 31, 2023 5 hours ago, Peaklander said: @Green200tdi you have said it’s a 1986 110 but has a TD5 loom. Are you or have you ‘fitted’ the loom? You appear to be sending this thread around the houses. No I’m just answering other questions, All I really needed was an answer why the door light wires weren't working, and as ever people start with diagrams and how to by pass the 10AS, as Ralph says my 1986 110 has a td5 compleat loom as the original was finished glowing fuses ect, I was unable to get my interior light to come on when I earthed out the two front door wires but the light would light when in the ON possision, I then was told thu other posts the 10AS would need to be connected for the light to work with the doors I’ve miss placed my 10AS Hope this clears things up. 😊👍 1 Quote Link to comment Share on other sites More sharing options...
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