RRC Shift Interlock Solenoid - Wont Shift Out of Park

StangGT5

Well-known member
Feb 4, 2019
132
43
Atlanta, GA
Does someone sell these transmission shift interlock solenoids anymore? Is there anyway to access the wiring to upgrade the voltage source without removing the center console? I think mine is gummed-up/worn out and could use replacing or more juice. A decade ago I had a Discovery I that would do this, and I ended up beating the pin out of the way. I'd rather try to keep the one working in this truck if possible.

I have a 1992 RRC and its shift interlock solenoid failures are getting annoying. The previous owner did not drive the truck much at all and they also installed a battery cut-off. I leave the truck stored with the cut-off in the off position. When I do drive it I have to press the brake 20-30 times to get the solenoid to let me shift out of park. A new brake light switch and fuses have made no noticeable difference. It does get better when I leave the battery connected and drive it more frequently. Though even then its not reliable.
 

robertf

Well-known member
Jan 22, 2006
4,609
242
-
On the Discovery the solenoid is only in north american vehicles, maybe RR is the same? Remove solenoid, and put it on the 'to do' list if it really bugs you.
 
  • Like
Reactions: Blueboy

Blueboy

Well-known member
Apr 20, 2004
3,035
377
Back in the USA; Rockwood, PA
Does someone sell these transmission shift interlock solenoids anymore? Is there anyway to access the wiring to upgrade the voltage source without removing the center console? I think mine is gummed-up/worn out and could use replacing or more juice. A decade ago I had a Discovery I that would do this, and I ended up beating the pin out of the way. I'd rather try to keep the one working in this truck if possible.

I have a 1992 RRC and its shift interlock solenoid failures are getting annoying. The previous owner did not drive the truck much at all and they also installed a battery cut-off. I leave the truck stored with the cut-off in the off position. When I do drive it I have to press the brake 20-30 times to get the solenoid to let me shift out of park. A new brake light switch and fuses have made no noticeable difference. It does get better when I leave the battery connected and drive it more frequently. Though even then its not reliable.
Not sure why you would want to keep this “feature”. I’d check with Will T and see what he could find for you. Possibly some WD 40 on the interlock plunger could also help.
 

robertf

Well-known member
Jan 22, 2006
4,609
242
-
AB indicates its the same from 92-02

I bought one from the dealer around 2004 when someone borrowed the car and loose change fell through a broken shift tape and trashed the wiring, but never got around to installing it and decided to delete the solenoid instead. It was much more expensive back then.
 
  • Like
Reactions: StangGT5

StangGT5

Well-known member
Feb 4, 2019
132
43
Atlanta, GA
AB indicates its the same from 92-02

I bought one from the dealer around 2004 when someone borrowed the car and loose change fell through a broken shift tape and trashed the wiring, but never got around to installing it and decided to delete the solenoid instead. It was much more expensive back then.
Do your brake lights work? I think that was usually the culprit.
Yep, the brake lights work fine. I installed a new brake light switch anyway with no improvement.

Hmm for $365 I might just remove it. I have another RRC that just started doing the same thing after I took a while doing a top-end rebuild, so I figured I'd see if these things could be bought and replaced.

I'm not crazy about a vehicle that can be taken out of park without the key, but I'm even less crazy about taking the shifter apart every time I want to drive one.
 
  • Like
Reactions: ukoffroad

Flyfish

Well-known member
Oct 29, 2004
1,360
194
51
St. Louis
The solenoid locking pin is spring loaded. You can just take a small strip of sheet metal between the pin and gear selector base so it can’t lock. Very quick and easy solution.
 
  • Like
Reactions: StangGT5

discostew

Well-known member
Sep 14, 2010
7,275
837
Northern Illinois
There’s a document called a SIDS document. It describes the system in great detail. If you can’t find it I’ll go digging for it. It stands for system information document. Theees a handful of them that cover engine management body controllers and stuff like that.
 
  • Like
Reactions: StangGT5

Blueboy

Well-known member
Apr 20, 2004
3,035
377
Back in the USA; Rockwood, PA
I'm not crazy about a vehicle that can be taken out of park without the key, but I'm even less crazy about taking the shifter apart every time I want to drive one.

Yep, first time it happened to me was on our property in bfe on a Sunday. Always carry the Workshop Manual and figured it out to get out of Park and back home.
For me lucky that it was the brake light switch and an easy fix.
 
  • Like
Reactions: StangGT5

StangGT5

Well-known member
Feb 4, 2019
132
43
Atlanta, GA
There’s a document called a SIDS document. It describes the system in great detail. If you can’t find it I’ll go digging for it. It stands for system information document. Theees a handful of them that cover engine management body controllers and stuff like that.
From what I can tell, the solenoid requires a power source from the ignition switch and brake pedal switch. I replaced both of these in the truck that has been doing it since I have owned it. My other RRC was working fine, then started doing it after sitting for a month. It has its original switches, so maybe it just got jealous of the other one. I swear these things sync cycles.

Because it will eventually work, I think it's more likely a lazy solenoid than a switch. The wiring I can see looks good, but I'll do some testing before I just remove the thing.
 
  • Like
Reactions: ptschram

discostew

Well-known member
Sep 14, 2010
7,275
837
Northern Illinois
Backprobe the circuit while it’s trying to operate the solenoid. I usually use it’s own ground so I’m really right in the circuit.
You can also test the windings in that solenoid if your amp meter has a good fuse in it. Power it up thru the meter and watch the amp draw of the solenoid. If it starts to climb it’s shorted. The amperage should go down a little as it warms up.
 

Blueboy

Well-known member
Apr 20, 2004
3,035
377
Back in the USA; Rockwood, PA
My other RRC was working fine, then started doing it after sitting for a month. It has its original switches, so maybe it just got jealous of the other one. I swear these things sync cycles.
My ‘94 LWB hibernates during the Winer for usually 4 months and have not had this issue. Even during the driving months probably only drive it maybe 5 times per month. Probably more luck than anything else still working! 😁 It sits next to the ‘96 D1 so has Rover company.
 
  • Like
Reactions: ptschram

StangGT5

Well-known member
Feb 4, 2019
132
43
Atlanta, GA
Backprobe the circuit while it’s trying to operate the solenoid. I usually use it’s own ground so I’m really right in the circuit.
You can also test the windings in that solenoid if your amp meter has a good fuse in it. Power it up thru the meter and watch the amp draw of the solenoid. If it starts to climb it’s shorted. The amperage should go down a little as it warms up.
What's the easiest way to access the wiring? I can see the front/pin side of solenoid in the RH side of the shifter bucket, but the solenoid itself is on the outside of the bucket. I don't see any wires going to that side of the console, so it seems like more disassembly is required.
 

discostew

Well-known member
Sep 14, 2010
7,275
837
Northern Illinois
What's the easiest way to access the wiring? I can see the front/pin side of solenoid in the RH side of the shifter bucket, but the solenoid itself is on the outside of the bucket. I don't see any wires going to that side of the console, so it seems like more disassembly is required.
Your going to need to get the console out. The hardest part of that is getting the park brake lever disconnected from the cable. I’ll look for that SIDS document for you. It’s been so long since I’ve had to look at one of these. Maybe we can figure out an easier place to get access to the circuit. The document basically splits the systems functions into 2 separate tasks. The first is not allow the shifter out of park if your not on the brake pedal. It’s other job is to make sure you can’t get the key turned far enough to remove the key if the vehicle is not in park.
 
  • Like
Reactions: StangGT5