charging and mixture/choke warning lights.

#1
How do i remove these lights from the instrument panel as they have what looks like some type of spring holding setup behind holding them in place. i would also like some information on the wiring set up on these two lights to get them back in working order.the wiring behind these lights have butchered some what. thanks in anticipation regards Derrick.Smith (deckell)
 

roverp480

Active Member
#2
Looking at the back of the lamp with the spring. Depress the spring including the collar at the top , this should reveal a sort of horseshoe shaped circlip which can be removed by sliding sideways . The collar and spring can now be lifted off and the lamp taken out from the front. The handbook or workshop manual has the wiring diagram and connections . The Rover Sports Register can supply the Workshop manual and Parts book and will post all over the world . Which year and model do you have?
 
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#3
Looking at the back of the lamp with the spring. Depress the spring including the collar at the top , this should reveal a sort of horseshoe shaped circlip which can be removed by sliding sideways . The collar and spring can now be lifted off and the lamp taken out from the front. The handbook or workshop manual has the wiring diagram and connections . The Rover Sports Register can supply the Workshop manual and Parts book and will post all over the world . Which year and model do you have?
Thank you for your advice,much appreciated. my rover is a 1949 P/3.
 

cobraboy

Well-Known Member
#4
As said, the spring pushes on a dished washer and inside the washer is the horseshoe shaped clip, you need to winkle the clip out from inside the dished washer to release the lamp unit.
Caution - the outer body has a very fine wire winding around it, this is a resistor to dim the bulb, it is very easy to break the wire winding when removing the spring and washer.
If the bulb is not working you change it by unscrewing the chrome bezel on the front, you do not need to remove the unit from the dashboard.

I would remove and test the bulb first, removing the whole unit is a last resort. They are expensive to buy new.
 
#5
As said, the spring pushes on a dished washer and inside the washer is the horseshoe shaped clip, you need to winkle the clip out from inside the dished washer to release the lamp unit.
Caution - the outer body has a very fine wire winding around it, this is a resistor to dim the bulb, it is very easy to break the wire winding when removing the spring and washer.
If the bulb is not working you change it by unscrewing the chrome bezel on the front, you do not need to remove the unit from the dashboard.

I would remove and test the bulb first, removing the whole unit is a last resort. They are expensive to buy new.
It looks like the wire is broken at one end. i am going to try and repair it.thanks for your advice.
 

cobraboy

Well-Known Member
#6
No Problem
You can make it work again by trying a repair, but it is not an easy fix. In case you try to just by pass the winding, which is doable, the light will work but the bulb will now be at full brightness and if illuminated for a long time will melt the front lens. The only way to get over this is to source the lowest wattage bulb in that type.
Yes I have messed with these lights quite a bit as they are common to a lot of old cars.
 
#7
No Problem
You can make it work again by trying a repair, but it is not an easy fix. In case you try to just by pass the winding, which is doable, the light will work but the bulb will now be at full brightness and if illuminated for a long time will melt the front lens. The only way to get over this is to source the lowest wattage bulb in that type.
Yes I have messed with these lights quite a bit as they are common to a lot of old cars.
On second thoughts i will try and make a new one, i can source some 28 gauge nichrome wire and make complete new one hopefully. would you have any idea of what length i would need to achieve the correct resistance that i would need to use a 2.4 or 3.6 watt bulb in these units.
 

roverp480

Active Member
#9
The original bulbs are 2.5 volt MES , like an old torch bulb. The resistance is to lower the voltage . You need to drop about 10 volts carrying about 0.8 amps so circa 12.5 ohm resistance (If my calculation is correct!)
 

colnerov

Well-Known Member
#10
Hi, A hundred years or so ago when I was at school we had what was called 'eureka' wire which was one ohm per inch. Presumably that nichrome is now called?

Colin
 

cobraboy

Well-Known Member
#12
I nearly suggested an LED - but I didn't :)
I can tell you it is depressing having a lens melt because of the heat from the bulb. The lens is Screwed directly onto the bulb which is spring loaded, so the LED would have to be the same length within a little.
 
#13
Well here i am again with some more stupid questions(just tell me when you good people have had enough of me). my repair idea of these lights was a failure. so i have purchased two low wattage bulbs and bulb holders. and have now drilled the original light fitting out to fit this new set up, still using the colored lenses and the spring retaining set up at the back of the units. the next question, can you give me a detailed wiring application diagram and the best way to proceed for the ignition light please. i have a work shop manual but it is not easy to decipher as all the wire covers behind the dash have faded and are now brown with no colors visible on them. i appreciate your help. best regards Derrick.Smith (deckell)
 

roverp480

Active Member
#14
As the wires are faded , the one way to determine which is which will be to refer to the wiring diagram and see where each wire originates and with a meter set to resistance check which gives a continuity reading.
The following is taken from the P3 wiring diagram and you need to check that your vehicle is the same. Anything could have been done in the last 60 years.
For starter's neither of the terminals or the bulb on these two lights should be connected to earth. Both the ignition light and the choke warning light should have one terminal connected to a wire, each connected to the same terminal on the ignition switch ( the terminal may be marked IG ), and the same terminal IG should have one other wire connected making 3 in total ( These would be white) . The other terminal on the choke light, is connected via a wire to the choke switch on the choke cable ( White with a blue trace) . The other terminal on the ignition warning light is connected to a wire which the other end is connected to the D terminal on the RF 95 Voltage regulator/cut out. ( Yellow wire) . You could get a new wiring loom with all the correct colours which makes making the connections a lot easier,
Hope that helps. If you are not sure get help from a professional as most of these wire are not fused .No guarantees given .
 
#15
As the wires are faded , the one way to determine which is which will be to refer to the wiring diagram and see where each wire originates and with a meter set to resistance check which gives a continuity reading.
The following is taken from the P3 wiring diagram and you need to check that your vehicle is the same. Anything could have been done in the last 60 years.
For starter's neither of the terminals or the bulb on these two lights should be connected to earth. Both the ignition light and the choke warning light should have one terminal connected to a wire, each connected to the same terminal on the ignition switch ( the terminal may be marked IG ), and the same terminal IG should have one other wire connected making 3 in total ( These would be white) . The other terminal on the choke light, is connected via a wire to the choke switch on the choke cable ( White with a blue trace) . The other terminal on the ignition warning light is connected to a wire which the other end is connected to the D terminal on the RF 95 Voltage regulator/cut out. ( Yellow wire) . You could get a new wiring loom with all the correct colours which makes making the connections a lot easier,
Hope that helps. If you are not sure get help from a professional as most of these wire are not fused .No guarantees given .
 
#16
Thank you roverp480 for your informative reply, as i can see now i did not explain myself very clearly. i was wondering if your reply still applies to the new setup with out the resistance coils on the body of the lights, which are now 12volts with very low wattage. thanks again best regards Derrick.Smith (deckell)
 
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