Speedometer not working

[1986PIONEER]

When my '86 Cherokee arrived from Arizona this fall the speedometer was working just fine. Now, speedo/odometer are only sometimes jumping a bit and then dead as a doornail. As with all early XJ's, I have the cable run speedometer. the Jeep also has cruise control so there are really two cables with a speed sensor in-between. I've had the cluster out and speedo removed, turning by hand it revs up just fine. for a cable test, I pulled the speedometer cable end and gear out of the transfer case and hooked my drill up to the cable....the speedometer worked absolutely fine. So it must be the gear, right? 19 tooth gear, factory original, looks a little worn. Teeth have a concave wear pattern. I get a new gear from quadratech, it's identical but with nice square teeth....put it in, speedometer works fine for about one block in my neighbrohood, then bounces a bit, and dead. cables are all connected and clicked in as should be. I'm all out of ideas.
The only thing I can think of is perhaps the corresponding gear inside the transfer case is bad?

 

[Saudade]

I think my speedo is possessed. Been having issues with it for a few years now. First time, it was very jumpy. Turned out to be old hardened grease in the gears. Once cleaned and regreased, it worked OK.

Thread ''88 Upper Speedo Cable Quest'

Dec 28, 2019

Been trying to remedy a jumpy and noisy speedo on my '88. Pulled the cluster out and cleaned out the speedo as well as washed out the stubby speedo cable (cruise control). The outer jacket is rock hard and inflexible. Plus the plastic conector that slips over the speedo is cracked.

The parts manual shows different part numbers for 87-early 89, vs late 89-90. The 90's seem plentiful.

I'd rather not bypass the cruise sensor and get the long cable (also plentiful).

Has anybody tried the '90s upper cable on their earlier XJ? Or better yet know of a source for the correct upper...

• Saudade
• Replies: 6
• Forum: OEM Tech Discussion

Flash forward a few years and it's at it again. This time it was frozen. Got it freed up and worked for a while, but it didn't last.

Thread 'Speedo Deado'

Jul 24, 2023

Sorry for the length of this post.

TL;DR

Speedo froze, not the cables or speedo drive at trans. Managed to free the drive in the speedo by soaking the end in some 91% IPA and spinning by hand and drill.
Seems fine now and speed reads consistent with GPS (on WAZE).

Full story

Went to do an errand and my speedo was stuck on zero. No movement, not even odo (not a DS9 reference). Thought maybe one of the cables broke. For those that don't have a Renix with cruise control, the speedo cable is in 2 parts, a short "upper" and a long "lower" cable. The upper clips onto the speedo. The...

• Saudade
• Replies: 4
• Forum: OEM Tech Discussion

Ended up finding a replacement in a local salvage yard. Grabbed the cables and CC speed sensor too. Odometer was 41K higher but it worked. All other components appeared good and seem to work OK.

 

[THE2NDXJ]

I know your rig is much older, but my wife's rig is a 1996 and was acting exactly as you are describing. I checked everything involved with the issue, and it turned out to be a bad ground wire. It ran from the cluster through the firewall, to the right side of the block. I relocated it, and the other grounds that were on the same stud, to the right side inner fender. I made a new ground stud closer to the back corner. Works great!

 

[Unclewolverine]

I know your rig is much older, but my wife's rig is a 1996 and was acting exactly as you are describing. I checked everything involved with the issue, and it turned out to be a bad ground wire. It ran from the cluster through the firewall, to the right side of the block. I relocated it, and the other grounds that were on the same stud, to the right side inner fender. I made a new ground stud closer to the back corner. Works great!

His is cable run. Completely different.

 

[1986PIONEER]

Correct, it is cable run…BUT. There is a spring clip connection that is pressed against the back of the speedometer housing (metal) and the clip is also connected to one of the paths of the printed circuit board. I find that strange. I assume it’s a ground, perhaps to keep a potential electrical charge from building within the speedometer thereby messing with the magnetic field that makes the needle rise and fall.
It’s just odd because there are only a few parts to this whole setup, and they all seem fine.

 

[1986PIONEER]

UPDATE: Took the Jeep out today for a half hour drive. The speedometer actually came to life a bit, albeit jumpy at first. I have a new theory: Cold Temperatures. The first time this happened was on a cold November morning when I drove it to get my new tires put on. And ever since it's been pretty cold. Today it was 40 degrees, kind of mild by comparison. And as the cabin heated up (I had the heat cranking) and the gauge cluster itself warmed up a bit, the needle totally smoothed out. Went by a "your speed" sign and it was dead on to what the speedometer was saying. So I feel like perhaps the lubricant in the gauge may get a little sticky in the cold after 38 years. Only time (and eventual spring temps) will tell for sure. I'm happy.