Interior Light

BX Tech talk
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Rob_e (UK)
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Post by Rob_e (UK) » Sat Nov 17, 2007 8:04 pm

Hi Ian,
Yes, I must admit the two sides doing different things is a bit confusing. I was working on the assumption that as docchevron1472 suggested perhaps the N/S light being on all the time was down to wires being the wrong way round perhaps.

If the circuit diagram is correct (fingers crossed) then the delay realy should have a seven pin multiplug on it, so if the one you disconnected only had five then perhaps this was something different. Does any thing else not work with that disconnected.

The switch on the light to put it on manually earths through a different circuit and does not go through the delay relay, so I would expect the light should switch on (drivers side for the moment) even with the delay relay disconnected.

Do you have the haynes manual/circuit diagram? I could scan the relevent part of the diagram in for you if it would help.

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Post by Ian_Fearn » Sat Nov 17, 2007 8:15 pm

I've got a Haynes but its not much use to me i'm afraid.

The strange part is that one is different to the other yet the wiring plugs are identical on each side and why would a previous owner have messed with it??

Can anybody confirm how many spades this relay should have???
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Post by AndersDK » Sun Nov 18, 2007 3:42 pm

Doc is on the right track I believe.

Firts of all - you need one of those simple needle tipped testlamps with a crocodile clip for earth connection. Its the most overlooked - and the most in-valuable - tool for the DIY car electrician 8)

First thing to do is unplugging ALL connectors AND bulb in BOTH lamp clusters :idea:

NOTE : REMEMBER to keep doors closed on the following test. Otherwise you will be fooled by the engaged door switches :shock:
NOTE 2 : do not insert or turn the ignition key. The interior lights circuit is a constantly fused live +12V circuit.

Working on each side's lamp cluster :
1) hook your test lamp clip on any nearby bolthead which would be earth.
2) test each of the connectors going to the lamp cluster. One connector should carry a constant live +12V - thus lighting up your testlamp.
This connector should hold a green wire with a black marker and/or a black connector shell.
3) fit this connector to the unswitched end of the bulb holder - the lower most spade in the bulb holder.
4) in case you can NOT find a connector carrying a live +12V, you have a problem with the +12V live circuit. First test is fuse F7 (white/20Amp or green/30Amin). Always replace despite how fine it looks - just to make sure. If still no joy - then you have a more serious problem with the +12V live wiring.
5) now remove the testlamp clip and hook it on to the +12V connection you just found and fitted to the bulb holder. The bulb holder may be a very convenient place to hook on the clip.
6) Check the remaining 2 connectors to the lamp cluster. One shold carry a constan earth. That would be a brown connector shell with a brown wire. Your testlamp should light up on this connector. Fit this connector to the SWITCHED spade on the upper bulb holder. Check that you can switch on/off your testlamp - checking the upper bulbholder.
7) in case you can not find an earthed connector - do up a new earth connection simply by connecting via an eye connector under any nearby earthed screw.

Now insert and check that the bulb will light up when the lamp switch is in either position (towards rear IIRC) check both bulbs making sure you are not fooled by a burned out bulb.
Copy your findings to the other lamp cluster.
Make sure the bulbs are left unswitched for now - i.e. waiting to take the door switch earth.

You are now left with a brown wire (I believe) - with a clear connector shell. This is the relay switched earth from the timer relay.
At this point check that this connector is "dead" - i.e. does not carry neither earth nor +12V.
Now open one of the doors and check that this connector is earthed by the door switch (activating the timer relay that is).
Connect the connector to the remaining spade in the lamp cluster. make sure this is the DIRECT spade connection to the upper bulb holder.

Further checks now includes that each fitted door switche should activate the interior lights - on both sides lamps.

If you can not make the connector with a clear connector shell active earthed - by opening a door - first check is the door switches - as described up thread.
Next check is the timer relay unit. It has a really bad habit of giving up the solder joints to the spade connectors. A simple re-soldering may give it another 10 years of service life.
Here are the relay connector connections :
(brown 7pole)
pin 1 : not used
pin 2 : green wire, brown marker, switched +12V from ignition switch (turns off the timing of the light)
pin 3 : green wire, blue marker, input from CL's - initiates the lights on un-locking
pin 4 : brown wire, white marker, all door switches in parallel - any earth from any door initiates the lights
pin 5 : brown wire, yellow marker, switched earth output to the lamp clusters
pin 6 : brown wire, no marker, chassis earth
pin 7 : green wire, no marker, +12V live (fuse F7)

Obviously if you cant recognise these wire colours/codes - its the wrong relay you have found :wink:
C U / Anders - '90red16riBreak - '91GrisDolment16meteor - Project'88red19trsBreak
dead cars : '89white 16RS - '89antrasitTRDturboEst - '90white19triBreak