leds in dash indicators problem.

jp928

Active Member
#1
Series 2, 74, D chassis. Putting LEDs in the dash, testing each as I go. Indicators have LEDs in the lamps, and have always flashed slowly. RH arrow bulb stays on, no sign of flashing, works OK with original bulb. LH arrow with LED, nothing. Anyt suggestions ? While I am here, what was the blck tape (with some sort of fibrous backing) along the top of the front plastic cover about? It was visibly curling, looking bad, with old age probably. Instrument panel doesnt want to come out - 2 philps head screws at the RH end need to come out? And one nut up under the cap? Noted before that the instrument removal (88.20.01) for strip speedo says to remove top facia rail (75.46.04) at step3; at 76.46.04 step 3 it says remove Instrument panel for circu;lar speedo models...???
thanks
Edit - got it out enough for what I want to do - pulling rightwards, wriggling. Cleaning the inside of the front cover is a pain - lots of wiping, trial in place, find more dust, clean again. Now to tackle the indicator problem.
 
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sdibbers

Well-Known Member
#2
Can’t help you on the circular speedo removal but on the indicators I can.
Those are classic symptoms of poor connections in the indicator system. First suspect would be the earth to the front indicators and their mazak housing. They tend to get pretty corroded from the back causing a poor return. After that go through the connectors and clean with a small wire brush followed with dielectric grease to preserve the contacts. The LEDs Will possibly not have enough resistance (yes even the dash ones) and that can also cause a problem for the flasher unit.
 

jp928

Active Member
#3
Thanks. Was planning to pull the multi wire connectors to the dash, clean and Deoxit them. If that doesnt fix, then check the earths at the light fittings. WSM doesnt mention the two screws at the RHS of the panel need removal.
 
#4
I fitted LED bulbs in the Indicators and experienced all sorts of odd problems till I fitted an electronic flasher unit to the flashers and the hazards , problem solved !
 

MikeMelb

Active Member
#6
Can't help with round instruments but with strip type the speedo cable or more specifically the 90degree connector seemed to be the limiter on movement.
 

jp928

Active Member
#7
indicators only work with original bulbs in place. No earth issues. Read somewhere that the Ign light needs to be a bulb to get charge - is this correct, even with 18ACR? Replaced the speedo angle drive while I was in there.
There is a bulb socket under-right of the clock - whats that for? No warning window above it, couldnt get it to light no matter what.
 

roverp480

Active Member
#8
An 18ACR needs a connection from the ignition to the alternator via the warning light to energise (Excite) the field coils. I am not sure of the exact amperage but the 2.2 watt ignition bulb is sufficient. A LED would not allow enough current to flow. I had this problem on a Land Rover when fitting an Alternator in place of a Dynamo. The original warning light on the particular model was a very low wattage , probably 0.5 watt and the alternator would not energise until it self excited at about 3000 engine rpm. Changed the light to a 2.2 watt and it excited straight away. One could use a LED as long as it was a bi- directional one and also fit a bypass resister to supply the current required to excite the field coils. I know we fitted a bypass resister on later Rover models as people were complaining of no charge, and it was because the bulb had failed and they hadn't noticed .
 
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jp928

Active Member
#9
Thanks, will leave the original bulb in there. Next - while dash was clear I could see a strange part attached to the dash end bracket - 2 red wires connected that seemed to be coming from rear of clock went to a piece of shiny metal , maybe 1" x 2", Smiths named, but couldnt read a part no; other side (facing centre of car) looked like a layer of plastic with metal traces on it. Thought at first it might be solid state voltage stabilizer, but there is one up the other end of the dash?
 

jp928

Active Member
#10
How are the 2 red leads connected to the ammeter - spades, nuts ? Unable to get it clear enough to see properly. Will have to get my mirror on a stick in there. I think I have marred the end of the oil pressure needle a touch....!@#$% Still works, but looks manky.
 
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