stazja01

First the car's specs:
1991 Dynasty LE
3.3 Chrysler V-6/4 spd auto (three with overdrive/electronically controlled)

A few times when I first got this car I had an issue where the speedometer would not work when the car was first started up but it would kick on about 10 minutes into the drive. It only happened a few times so I didn't think anything of it. It has not happened for quite some time.

A few days ago I got into the car and the speedo wasn't working. I drove for 30+ minutes and it still wasn't working. I shut off the car and drove it the next day to and from work and still no dice. I've been driving for three or four days without the speedometer and it still hasn't kicked back on. The cruise control does not work (it worked just fine before) and the electric locks don't automatically lock like they used to (I think around 15 mph or so).

Does anyone have any idea what this could be? I'm not sure if this car even has a traditional mechanical speedometer cable or if it is completely electronic. Is it possible that a relay or fuse has died and if so where should I be looking? The fact that the speedo, cruise, and auto locking feature all stopped working leads me to believe that the problem isn't in the dash (especially since all of the other gauges work). Any help would be appreciated. I've been using my GPS as a speedometer but I would love to have my cruise and odometer back. Plus I think this might hurt me at inspection down the road.

scotts74birds

Off the top of my head, transmission output speed sensor, or associated circuit. If so equipped. I'll double check tomorrow, but it seems to tie every symptom together.

stazja01

I appreciate the info. Unfortunately, my Haynes manual is useless on the subject... Not even a photo or diagram except of the mechanical speedometer cable. It mentions the electrical ones briefly but doesn't really have any information about them. I'll have to do some digging and see if I can find out what I'm looking for.

scotts74birds

Speedo is driven electronically by the vehicle speed sensor,[VSS]. The door locks are controlled by the body control module [BCM]. the bcm will lock the doors when vehicle speed reaches 15mph. The BCM cant know what the speed is without an input from the VSS. While I cant find it in the factory manual, Im sure that the cruise must require some input of vehicle speed to function. Checking the VSS, and its connections and related circuitry would be a good place to start. The VSS is located on the transmission, near the output shaft.

stazja01

Any idea how to test the speed sensor? I have a multimeter and know how to test voltage and continuity if that helps. Thanks again for the information. I did a search on advance auto's website and found some sensors to get an idea of what they look like.

http://shop.advanceautoparts.com/web...m=speed+sensor

Unfortunately, it's about 20 degrees with snow on the ground here. I changed a starter for someone in weather like this a few years ago and I'll never do it again. Hopefully we get a warm spell for a day or two and I can deal with this. Either that, or I'll call a mechanic friend and see if he can squeeze me in.

scotts74birds

On most of them is a pos, a neg, and a signal terminal. When a piece of metal is placed closely, it will allow a voltage down the signal term. I dont know if its a full 12v, or just a signal voltage. Sometimes there will be a visible sign of heat damage to it. Bulging or blistered. It should test just like a crankshaft position sensor if you have a manual that covers that.

scotts74birds

On most of them is a pos, a neg, and a signal terminal. When a piece of metal is placed closely, it will allow a voltage down the signal term. I dont know if its a full 12v, or just a signal voltage. Sometimes there will be a visible sign of heat damage to it. Bulging or blistered. It should test just like a crankshaft position sensor, I'm sure the Haynes manual covers that. You did check all fuses in the car and under the hood?

stazja01

No I haven't but that's a good call. It would be nice if that's all that went wrong.

stazja01

So... It's been way too cold for me to be outside in the snow trying to find fuses and sensors so I took it to a mechanic friend of mine. He tried the fuses with no luck. Same with the sensor. He actually replaced it with a new one and the situation has not improved. He also checked the wiring to make sure there were no breaks. At this point, he's looking for a technical manual for the car because he is all out of ideas. Are there any relays around that might cause this sort of issue if they failed?

stazja01

Another issue that may or may not mean anything:

I'm pretty sure my low fuel light used to come on and stay on until the car was turned off, even when the fuel sloshed around in the tank. Now it turns on and off when the fuel is borderline low and I take a corner or accelerate quickly. This seems like the work of a relay and since the speedo/odometer aren't working either maybe they are connected. Anyone have any ideas?

stazja01

*bump*

Anyone? I'm still stumped and the mechanic has no clue. Even if someone could point me towards a technical manual or wiring diagram it would be appreciated. Something electrical seems to have failed but we're just not sure where to look.

scotts74birds

What years was that model made? I may have a set of 93 factory books for it. I have 93 Service Manual, Front Wheel Drive Car, Engine,Chassis, body, and the one for Electrical, fuel and emissions.

stazja01

It's a 91. I think most of the later changes to the car (air bag, etc.) had occured by then so a 93 manual would probably be ok.

stazja01

Sorry, I see what you were asking now. Dynasties were built from 88-93.

stazja01

So... I am still having this problem. The only update that I have is that the trip odometer moved 4/10 of a mile and the regular odometer flipped over one mile. It's almost as if everything is connected but reading way too slow. I have no experience with electronic transmissions so any information would be appreciated.

claudebarnhart

This is an old thread, but maybe someone will pick up on it, if they've solved this problem:

1992 Dynasty 3.3/4-speedOD; speedo goes whacko for the first several minutes (cold conditions, temp 30F), after warm up speedo seems to op normal, but odometer has quit.

I did install a new VSS and the problem was less, but speedo still not quite right until after warm-up.

Any thoughts/solutions for this problem????

*Installed both input & ouput VSS - speedo indicates about 10mph fast at 65mph; odometer and trip counter still do not work; cruise control holds whatever speed set on; transmission seems to shift normally !!!!

Still baffled.

Dummkopf - no longer baffled - I had neglected to disconnect the battery, in order to let the computer recognize the new parts. I disconnected the battery (:20) reconnected and drove through several start/stops, and the speedo now agrees with my GPS.

Barney
barney@claudebarnhart.com