75ZT Community

Evening all,

Here's a new one on me,

On my R75 auto i noticed that the gear selector light is not working and showing what gear you're in, I also worked out that I don't have reverse lights.

I have not come across the gear selector light not working before, so do we think its the reverse switch on the gearbox or is there a common fuse linking them.

Thanks

There seems to be one fuse, but it looks like it powers the auto transmission ECU (Engine Control Unit) as well so if it were gone I'd expect you to have other problems too. Does the indication in the IPK (Instrument pack (IPK from the German)) still work OK?

Do you hear the relay in or behind the IPK clonk as you change gear while stationary? The indicator light and IPK indicator letter comes on at the same moment.

Duncan wrote:There seems to be one fuse, but it looks like it powers the auto transmission ECU as well so if it were gone I'd expect you to have other problems too. Does the indication in the IPK still work OK?

Hi Duncan,

No other problems when driving.
The gear your in shows in the IPK.

Just in from a 12hr day working up London so not had a chance to check the fuse.

Thanks

Mick wrote:Do you hear the relay in or behind the IPK clonk as you change gear while stationary? The indicator light and IPK indicator letter comes on at the same moment.

Can't say i noticed anything but will have a listen when I back in it.

Thanks

There's not an obvious connection between the two. Does the backlighting (amber) in the selector display come on?

Just an update,

Well no update yet as i have not had chance to check due to work.

I'm off tomorrow so will have a play about and let you guys now the outcome.

Thanks

Evening all,

Still not fixed due to work and family oh and the small matter of enjoying the sunshine

Well after a playing around in the fuse box I eventually found a blow 5A fuse on number 23 this was after my Haynes manual told me it was a 10A.

Sods law I have every other fuse apart from a 5A


After looking around the bay at fuses I see they not make a mini blade fuse that has a LED (Light Emitting Diode) built in to it that glows when the fuse is blown to show you what fuse has blown nice and easy.

Has anyone used theses led fuses before or what do you think about them ?

Well that's right for the reverse lamps, but doesn't explain the selector lights. Maybe there's something that the manual doesn't show, won't be the first time.

Never used the LED fuses so can't comment on them.

Right I’m going to get a fuse on my way home from work and see if it fixes all the problems.
One thing I’ve read is that on the auto's the reverses light switch in not built on to the gearbox but built in to the gear selector, Has anyone come across this before ?


I might get a load of these LED mini blade fuses and replace them all in my car

Well I got a new fuse and everything is working again,

So on a R75 auto the reverse light and the auto gear selector indicator are on the same fuse which is a 5A number 23.

Good to know. Yes, I believe the reverse switch is in the selector. On the autos there's a relay for reverse lamps which isn't there on the manual box. That's because the switch in the selector (which incidentally is on top of the gearbox, not under the lever) can't handle the bulb currents.

There is a supply from Fuse 23 to the selector indicator, but the way it's drawn on the circuit diagrams, the selector indication LEDs are supplied by the gearbox supply. It doesn't show the feed from 23 being used at all, but of course it must be there for something. I have know things before where the way things are drawn, oversimplifies and ends up being confusing. The cooling fans have similar problems and are just plain wrong.