auto transmission fuse keeps blowing

[martynhaden]

Help! as a newby and someone who doesn't understand a thing about how cars work, I'd love to know if anyone else has experienced a similar problem. We have a 10 year old terrano 11 se+ and love it, all except for one very frustrating problem. More often than not when ever we engage reverse the auto transmission (10amp) fuse blows and; if the car is running it adopts the get you home mode, or it won't start. It doesn't matter what the weather is doing, whether the car is warm or cold and I've tried removing the reversing bulb. It's costing me a fortune in fuses. Any ideas anyone?

[wildbri]

Hi sorry that you have this problem, my terrano is manual so I can't look at the circuit. You need to look at a circuit diagram to see just what that fuse protects, possible a gearbox control. Some one with an auto will pick this up later in the day and offer advice, there's always an answer, although it may cause some discussion on here, less you are lucky and some one as already had this problem and knows the cure.. regards bri

[macabethiel]

Has the vehicle had a tow bar fitted ?

I would be looking for trapped cable somewhere at the back?

Have you located the reversing light switch and disconnected this from the circuit?

Is the reverse gear engaged purely mechanically or by solenoid as is the way with some modern gearboxes ?

Have you spoken to the previous owner could it be linked to the addidtion of some sort of electric device.

Is there a data port on the gearbox ? If there is has the heat from the exhust system damaged the wiring.

I have never hear of this problem before so just giving areas I would investigate.

[iandouglas]

hi Martyn.
when fuse blows can you still select reverse and forward gears and park ?
does it blow fuse every time ? or is it intermittent?
does it start with blown fuse?
If so then I would think the gear selector will be manual.
It would seem that when you select reverse the wiring from fuse to reverse switch on gearbox or reversing lights has a short circuit which is tripping the fuse.
So can you find the reversing light switch on the gearbox and disconnect it.
There may be other wiring plugs on gearbox for start inhibit and perhaps overdrive/ eco mode.
So a little investigating is required .
then if disconnecting reversing light wiring cures the fuse blowing ,look for trapped chaffed wiring .
I am not sure if the switch will have a live feed (ignition on)use a test lamp .
if so try just disconnecting the other side of switch.
If so you could re wire that side back to reversing lights.
I would think that power will flow through top of fuse bank ,through fuse, then to gearbox switch then to rear lights.
good look with it hope the above helps.
rgds.iandouglas

[macabethiel]

Not sure if you have cured your problem but woke up this morning with an idea.

If your auto is like mine it has an overdrive switch in the gear selection knob ?

The wiring for this o/d switch runs down the gearlever shaft and then crosses the selection gate mechanism and to a wiring block on the inside of the transmission tunnel. The wiring is very light so its flexible and could get trapped in the mechanism. When you select reverse you could be trapping this wiring as it at the extreme end of its movement ?

Might be worth unplugging this to see if it makes any difference. Its not a big job to loosen the centre consul and see inside takes about 15 minutes to undo the screws etc.

[martynhaden]

Has the vehicle had a tow bar fitted ?

I would be looking for trapped cable somewhere at the back?

Have you located the reversing light switch and disconnected this from the circuit?

Is the reverse gear engaged purely mechanically or by solenoid as is the way with some modern gearboxes ?

Have you spoken to the previous owner could it be linked to the addidtion of some sort of electric device.

Is there a data port on the gearbox ? If there is has the heat from the exhust system damaged the wiring.

I have never hear of this problem before so just giving areas I would investigate.
Thanks for the thoughts will explore and let you know

[martynhaden]

hi Martyn.
when fuse blows can you still select reverse and forward gears and park ?
does it blow fuse every time ? or is it intermittent?
does it start with blown fuse?
If so then I would think the gear selector will be manual.
It would seem that when you select reverse the wiring from fuse to reverse switch on gearbox or reversing lights has a short circuit which is tripping the fuse.
So can you find the reversing light switch on the gearbox and disconnect it.
There may be other wiring plugs on gearbox for start inhibit and perhaps overdrive/ eco mode.
So a little investigating is required .
then if disconnecting reversing light wiring cures the fuse blowing ,look for trapped chaffed wiring .
I am not sure if the switch will have a live feed (ignition on)use a test lamp .
if so try just disconnecting the other side of switch.
If so you could re wire that side back to reversing lights.
I would think that power will flow through top of fuse bank ,through fuse, then to gearbox switch then to rear lights.
good look with it hope the above helps.
rgds.iandouglas
Thanks for that will invetigate and let you know