Automotive → 2000 Dodge Grand Caravan ES Speedo/Tach not Working

Have searched the Internet high and low and come across several references to the connector on the instrument cluster being notorious for faulty/broken solder connections. I disassembled the dash, removed the cluster, re-soldered the pins on the main connector, and reinstalled.

Still no tach or speedometer.

If I hold down the trip/reset button and turn the key on the dash does go through diag mode, all lights come on, and the needles for the tach and speedo move.

Is there a sending unit somewhere that the instrument cluster may not be getting signal from? How would I check to see if the instrument cluster is getting the info in the first place?

Other ideas or suggestions?

This particular caravan has the autostick (4 spd) feature on the transmission, so the instrument cluster is harder to come by. I did find one available on Ebay for $75, but I'd hate to throw $75 at it for diagnostic purposes.

Help!

Does it have a vss sensor? My ford van did the same thing--lost tach and speedo.

Well, a quick Google search tells me that there is a main vehicle speed sensor, and an input and output transmission speed sensor. Would it be safe to assume that the main vehicle speed sensor would be sending data to the instrument cluster for the speedometer?

That wouldn't explain why the tach isn't working either.......

Is it just the tach and speedo not working or does the whole dash not work? Given the vintage your gauge cluster should be PCI based meaning all sensors go through the ECU and all the data is fed on a 1/2 wire digital bus to the cluster to parse. So if everything is dead, it is that connection somewhere. If it is just the tach/speedo and everything else functions and the cluster test works, it is the tach/speedo sensors somewhere along the line.

Another thing is if you can get a hold of a diagnostic tool (I use a cheap ~$15 bluetooth OBD dongle and Torque on my phone which is free for basic stuff) and view the tach and vehicle speed there and see if they are reported. If they are also showing nada, that is a dead giveaway on the sensors.

EDIT: I should also note that if it is the bus connection to the cluster, you'd be seeing more issues. If it has the digital odometer display it would be showing a 'NO BUS' message which would be a dead giveaway.

Just a few things for you to chew on.

If the transmission input and/or output sensors had gone bad, it would cause the transmission to go into "limp home" mode, (won't shift higher than second gear). If this is not the case with yours, then the input / output sensors are OK. I went through an output sensor on my '99, and this is what happened.

The instrument cluster itself works. Fuel guage, temp, transmission indicators, odometer, lights.... It's just the speedo and tach.

Where did you source the diagnostic dongle? Sounds like a good tool for me to have on hand.

If it were a sensor malfunctioning, and since it shifts well it would not be the transmission input/output sensors, what other sensor(s) could it be?

Just search for 'Bluetooth OBD2' on Amazon. Unless you are doing complex and extensive reading, the cheapest dongles work just fine. They tend to become real slow in reads when pulling many sensors at once and will occasionally 'disconnect' from the ECU and take a second or two to pick back up. But this is a non-issue for many people. It is, indeed, a handy tool to have in the kit. I leave mine plugged in all the time. Just have to open Torque on my phone and that is it.

OT: I actually use mine all the time as a trip computer as my car doesn't have one. Have one page on my Torque display which has current fuel level, distance to empty based on instantaneous MPG, and instant MPG. Accurate from what I can tell.

Another small shot in the dark/curiosity: Does the odometer/trip meter still increment normally?

VSS sensor--it will shift fine without it.

Found the sensor you're referring to and ordered it from Amazon. Cool trick on the trip computer substitue, btw.

Yes, the odometer and trip meter function properly.

Also, today I replaced the clock spring as the horn, cruise, etc were not working. The air bag light is now off, horn works, audio controls work, and.... cruise works great.

I assume that means the sensor that measures road speed is working correctly, since something has to be telling the cruise module what speed to maintain, correct?

Since it's working, is it still worth trying a replacement of the VSS?

Also, where does the tach get it's information?

I can't guarantee thats the problem but would spend the cash to get the computer read first. Some auto part places wll scan it for free.