Auto Gear Selector Indicator

[MikeJohn]

The red led indicator next to the gear selector that should show Park/Drive/Neutral etc has unfortunately stopped displaying anything. No leds light up at all to indicate gear position.

When the car lights are on - the P/R/D/1 etc light up white OK, but no Red LED next to any of them.

The Dash display is fine, but I find I tend to use the one next to the gear lever when reversing etc.

I have tried swapping the display unit for another (2nd hand but allegedly OK) and that suffers the same problem, which together with the dash display working makes me thing the switch on the gearbox must be OK, and the most likely fault is a simple corroded joint somewhere.

Any suggestions where to look?, or any knowldge as to what voltages should be present on what pins at the indicator to start tracing it back would be welcomed.

Many thanks

Mike

[Thomas]

The red led indicator next to the gear selector that should show Park/Drive/Neutral etc has unfortunately stopped displaying anything. No leds light up at all to indicate gear position.

When the car lights are on - the P/R/D/1 etc light up white OK, but no Red LED next to any of them.

The Dash display is fine, but I find I tend to use the one next to the gear lever when reversing etc.

I have tried swapping the display unit for another (2nd hand but allegedly OK) and that suffers the same problem, which together with the dash display working makes me thing the switch on the gearbox must be OK, and the most likely fault is a simple corroded joint somewhere.

Any suggestions where to look?, or any knowldge as to what voltages should be present on what pins at the indicator to start tracing it back would be welcomed.

Many thanks

Mike

Hi Mike

this happened to me and it was simply a blown fuse, if you have the old style fusebox its the set at the top left of the fusebox behind the glovebox. although im sorry I cant remember what fuse number it is.

[MikeJohn]

Thanks for the suggestion,

I will dig round fuses tonight. I had not thought to look for a fuse as everything else is working fine, and having a fuse just for that function seems a bit surprising.

I'll let you know what I find!

Mike

[MikeJohn]

No Joy on finding a dead fuse unfortunately. Can you recall what rating it was?

Next step is actually test every fuse rsther than just a visual check with head upside down, and back getting wet as it had started raining!

Mike

[Thomas]

Hi Mike, pretty sure it was a 10amp, recalling back in sure it was the same one from my cruise control.

[MikeJohn]

FIXED IT

Thanks for the help Thomas, it was close, not quite right but got me hunting in the right place.

The short answer is the Reversing lights fuse feeds a permanent live to the gearbox indicator lights - why is anybody's guess as it also gets 8 other live feeds under different circumstances. I thought I had checked all likely fuses, but had not checked that one.

The longer answer if anybody is interested is:

I bought another light assembly of ebay as I had convinced myself it had to be that at fault. The "new" unit had exhibited the same problem.

As it was unlikely 2 had failed in the same way I dismantled the ebay unot to work ouit what all the connections did. Most are pretty obvious, one earth, 7 12v feeds (1 per gear light) and 1 12v feed for illuminating things at night. Oddly there are 5 suface mount transistors in there as well - it all seems a bit complex for something that appears so simple.

I was happy to poke about with the spare unit and eventually worked out that the leds only light if 12v is present on the correct signal wire - 1 per gear setting, AND 12v present on pin 6 (plus a neg on pin 4) - pin 6 turns out to be the wire from the reverse lamp fuse... Note this is NOT the reversing lights - ie only 12v when the lights on - it must come from the same fuse in the fusebox as the reverse lights but before the relay that controls them.

So an auto 75 has an inbuilt warning that tells you if your reversing lamps have fused! What I cannot work out is why the designers stole a power feed from ther rather than the instruments, of cigar lighter - all of 12 inches away, or many other places.

Anyway - I hope this is useful to somebody else, and I am really pleased to have found it before I ordered a new lightbox unit.

Why had the fuse gone? I suspect new caravan - which has reversing lights - the old one did not. Trailer wiring is the proper MG Rover unit so I would heve expected all to be OK, but since the reverse lights are not on the fancy bulb failure system I suppose they may have just taken the feed direct rather than via a relay - which would certainly explain why a 5 amp fuse gave up. 4 * 21watt bulbs will draw as near as makes no difference 8 amps. Has anyone seen any advice to replace the reverse lamp fuse with a 10 amp one if towing a trailer with reversing lights?

So more investigation needed on van reverse lights etc, and maybe add a small relay in the boot, but that is all easy now I know what the cause was!

Thanks again


Mike

[Thomas]

Hi Mike, glad you got to the bottom of it and it wasnt anything major to fix! :}