Hello All,

I have a 1997 Disco with a standard North American gasoline 4.0 V8 motor with an automatic transmission. Recently my Tachometer, Speedometer, and temperature gauges have all stopped working. I found that my #14 fuse under the steering column (10amp) had blown. I replaced the fuse and it took it for a test ride. It blew again so there is probably a short somewhere.

I replaced the fuse again and this time paid very close attention to possible causes of the short. I started the car up and the tach worked. But as soon as I moved the shifter from Park into gear, the tach immediately went dead, even before I moved the car. So my hunch is that there is a short somewhere in the shifter or related switches.

Also, there was another symptom that was present before the fuse blew out - Two weeks before the fuse blew out, the car would not start in park. To remedy this, I would turn the key to the on position, put my foot on the brake, and them moved the shifter from park down to 1st and back to park. Then the car would start. I am not sure that these two problems are related but I think that they might be.

Last night I took the center console apart and found this switch in the shifter assembly area. (see photos) This switch has a little wheel on the bottom. I determined when the little wheel is in the up position, it causes a pin to retract and allows for the shifter to move into gear. Can somebody tell me the name of this switch? Since this is a wear and tear part, I am thinking that this switch my be the cause of my short, but it is only a hunch.

Sorry about the poor photos. I should have taken a pic before I took the switch out. It was mounted to the right of the shifter.

 

"Can somebody tell me the name of this switch?"


It's the Micro Switch for the Shifter Interlock. I think the part number is PRC9677 or PRC9859.

 

Not a cheap switch! $100 or more. I guess I better make sure this causing my short.

If this is not short circuiting, then what else could it be?

 

I did more poking around tonight. I have determined that the short is NOT being caused by the Interlock switch. I put another fuse in and tried the switch a number of times. It had no effect on the operational tachometer.

I checked the shift lever release button by itself several times and that had no effect either. It's not until I move the shifter that it blows the fuse.

But the rabbit hole goes deeper as now the car is having some difficulty starting. The solution seems to be to hold the shift lever release button in (actually, it is pulled up since the T handle has been removed.) And then it may start.

Interestingly, there is a small amount of smoke coming off of the parking brake cable when I am trying to start it. It happens only when I am not pulling up on the shift lever release.

Tomorrow, I will dig deeper and see if there is a wire or switch going to the parking brake cable. By the way, I never use my parking brake because it won't budge when I try to engage it. I never thought it would be an issue since the truck is an automatic and setting into park seems safe enough.

 

I haven't had this problem. But find out where the smoke is coming from and there is a good chance that your short will be there. Was looking over the electrical manual and F 14 looks to feed the VSS. That is the only thing that I can think of that might be down below the parking brake.

I also have an automatic and use the parking brake quite a bit. Especially since I have been working on the drive shafts lately. Also handy when parked on steep hills.

Do you have a copy of the electrical manual?

 

Sounds like your ignition switch. I've seen bad ignition switches cause the gauges to die