Speedometer reads 45 sitting still

I have had the same old problem that everyone else has had with the dash
lights going out for the past two years (will be fixing after reading
forum), but now the speedometer is about 40+mph above whatever I am
driving. If I am doing 50mph it it telling me that I am doing 90 etc.
Also the fuel gauge is reading way above "F" once the key is turned to
the last position prior to starting. If the key is in accessory the
fuel gauge reads 1/2 tank. "
When I disconnected the fuel sending unit the needle would go from way
above "F" to 1/2 tank.
Would this be another result of the solder joints going bad? I have
read that a bad relay for the rear window defroster can cause faulty
readings on the instrument panel and didn't know if anyone else has had
this problem. Thanks for the help.

97 Town & Country 3.8L 145,000 miles

 

For the speedometer problem, do this:

Start with ignition switch off (in "lock" position). While holding the
odometer reset stem in, turn the key to the "unlock" position (that's
the first click of the ignition switch) - continue to hold the odoemter
reset stem in for about 3 seconds. You'll see a self-test of the
instrument cluster begin - part of which includes a dance of the gage
needles to preset positions. At the end of the needle dance, the
tachometer needle will be in its proper position.

In a nutshell, here's what happened (no need to read further if you
don't want to know the "why" of what happened):
The needle somehow got thrown into the wrong position (say - a jolt to
the vehicle with power turned off). The gage needles are driven by
motors that have any one of three unique positions (at 120° intervals)
for a given set of their control signals. Everything is great
until/unless the needle gets into the wrong 120° sector - and then you
see what you are now seeing. Putting the cluster thru the self-test
(needle dance) tries to force the needle clockwise past the peg, but
since it is blocked by the peg, the needle pops back into the correct
sector and forever will read correctly (unless something jolts it into
the wrong sector with ignition power not applied to the cluster).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Bill, thank you for the reply. I removed the instrument cluster today
and resoldered the pin connections. This appears to have fixed the dash
lights from going out and perhaps I will no longer have to beat
itrunaround . I reset the panel as you instructed about 4 seperate
times with no results(no codes just 999). Both the speedometer and fuel
gauge needles did their dance but they always go back to the same spot
until I turn the key off. When the key is turned off there is about a
two second delay then you can here a click and both needles fall back
to zero. The click sounds like it is comming from the instrument panel
or behind it(not the engine compartment). I reset the PCM as well as
the BCM and when that didn't work I disconnected the battery for about
10 minutes with no results. Could this be the result of two years of
poundings on the dash?
It could be coincidence but about the same time this happend the van
will run like *hit for about 10min when you first start it up. I just
had the fuel pump and filter changed because it wouldn't run so I
belive that is from trash in the tank. There is a code 11 on the PCM
which I belive is a crank position sensor which I will change here
shortly. Any ideas?

Almost forgot, I changed the rear window heated backlight relay (rear
defrsot)which did nothing but cost me $17.00. When I hit the defrost
the rear wiper comes on.

 

I'm out of ideas, except bad BCM.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')