Hi,

I just picked up a 92 Laredo. My symptoms are Speedometer will only go to about 25 - 30 mph. The odometer turns very slowly and the tach also will only read up to 1000 rpm and the cruise control is not working. The overhead Temp and direction are usually blank, every once in a while it will show a couple of dots and only once have I ever seen it display correctly. Do these symptoms seem like ground problem? I am about to go outside and try to find the 3 wires near the distributor on the motor. Is there an easy way to test if the ground wires are working correctly? Or does this seem like a Speed Sensor issue on the transfer case or lastly needing to clean connections on the gauge cluster? I have searched a ton through the forums, however everything I find is usually related to complete failure. Any help would be very appreciated.

Thanks,

Brent

 

Hmmm. The speedo and odometer are driven off the speed sensor. The Tach is driven by the PCM. Overhead display isn't related to either of them. Chassis ground is common to all of them though.
I believe there's a ground for the instrument cluster too although I've never gone looking for it. Perhaps a general ground & connector cleaning and refreshing would be a good place to start.

 

Well I drove it in to work today and I reported incorrectly about the tach. It is working correctly. I guess I hadn't really looked down while accelerating, only when up to speed. Today I had a nice open road and decided to punch it. The tach worked as it should. One less thing to worry about. I will begin looking for Speed Sensor troubleshooting or just replace it if I cannot find anything further info. I will look at the temp and compass separately when I re-glue the sagging headliner.

Thanks so much for taking the time to respond.

Brent

 

Didn't some '92s have a cable driven speedo?

 

I am not sure. How can I tell?

Brent

 

Crawl underneath and you'll find the speedometer on the main output of the transfer case on the driver's side. Either there'll be a large cable or an electrical connector on it.

 

I will check it when I get home this evening. Thanks!

 

If it does I bet it's a 2-piece cable with the cruise transducer in between. Might explain that failure too.

 

I have the electronic driven speedo. I crawled under, unhooked it and drove around the block, completely dead. Plugged it back in and took another lap and it is still behaving like before. When I am going around 30 it reads 5-10, 45 reads 25, 55-60 reads 35. I will take apart the dash this weekend and see if anything is loose on the back of the speedo. If anyone can think of anything else to try, please do not hesitate.

Thanks for all of your help.

Brent

 

I'd go back to what Radi mentioned with grounds. In my humble opinion the XJ's grounds were insufficient in the first place. You can find some good electrical tips here: https://www.cherokeeforum.com/f51/cr...x-tips-153657/ It's written for 1987-1990 model year Cherokees but much of it applies to the later models as well. It should get you on the right path.

 

Thanks so much for your help and the link. I love the Hunter S. Thompson quote by the way.

Brent

 

No problem, I hope thats all it takes. Don't be surprised if your Jeep runs better once that's all sorted!

Just another freak in the freak kingdom.