Speedometer

I replaced the speed pickup in my 91' Dynastry. Still having speedometer
problems. Speedometer seems to work when lights or on high beams, or if I
flash to pass. However, some days it will work. Other days, even the
tricks with the lights don't help. Any thoughts or advice appreciated.

Chris

 

You are loosing either ground or power to the instrument cluster.
When you flash the high beams you are supplying a small amount of
additional power or ground through the blue high beam bulb. Sometimes
this is enough to make the cluster operate. I do not have the wiring
harness schematic for that model year car so I can not tell if it is
the ground or the power but it is one or the other.
Around this model year there was a problem internal to the cluster
where a power resistor got too hot and fractured the solder on it's
leads. If the resistors leads are resoldered it would again work for
several years.

 

Thank you,

This is more information than I've ever been able to find on this problem!

Any idea where I would find the resistor you refer to or how I could further
track it down. Have multimeter, and know how to use it. Have soldering
iron as well. Have had instrument cluster out, and will take it out again.
Just haven't got the foggiest where to look.

My blue high beam bulb doesn't work - any chance it's related?

Chris

 

Is there any chance this TSB addresses my problem?

http://dodgeram.info/tsb/1991/08-10-91.htm

The connection to the speed sensor seems good. Connectors are clean. I
just installed a new speed sensor, and I had the same old problems
immediately. I would have expected the terminals would need some time to
corrode before I would see problems again.

Chris

 

You *might* also consider soldering the contacts together or possibly creating
shunts with small pieces of wire or omething if it is really bad.

What happened in my case - I pulled the cluster and fixed it - and the first
major bump I hit, it went loose again. Tommorrow I solder the thing down
hard. If it breaks again, I have a desoldering tool or will get a new
one with a tach in it from the junkyard.

 

If you purchased the sensor from a Cry. dealer it will com with a new
pigtail connector.

 

Thank you,

Could you give me more specifics as to what you are soldering in the
instrument cluster? I've had it apart, and didn't notice any obvious
problems. However, if I know where to look, I might spot it.

Chris

 

I did purchase from a Chrysler dealer, but no new pigtail connector with
it......$96 CND.

Chris

 

The connectors - three of them - the backsides of the connectors.

Also, you see where the board slides over the pins coming out of the
gauges themselves? Those get loose too. *usually* crimping the
contacts they slide into makes them tight enough. In my case, not.
A drop of solder should be adequate.

Also look for blown solder joints or components. A magnifying glass
is pretty much required.

 

Thank you,

Will take a look.

Chris