Hello,

I found 2 dashs from junkyard to replace, but after swapped, the speedometer still not working, why is that??

It's a used 1989 Firebird V6, the needles work fine, there is not other wire or connecting behind the dash!!

thanks

Joe

 

That's ok.
My Wife is from Singapore & I solved her 1968 Camaro problems, too.
She married a cheap mechainic.
When ya go from one dash to another
SOMETIMES
The wiring plugs (in the wiring harness) you connect will be "different".
Example.
I have a 1985 Firebird (mechanical speedometer) with the light dash (no gauges).
I have another dash (like you, same story), that is the "Gauge" version.
To make gauges work correctly, I must modify the original "light dash" vehicle wiring harness.
That MAY mean finding the "right" wire and moving (in the connection plug) a few spaces this way or that way.
You need a wiring schematic for this mission.
Those wiring diagrams are in the factory shop manuals, the Helms manuals (www.helms.com).
Or maybe a Good Buddy, here, can solve this better.

 

Thanks alot, btw, Is your wife a Chinese ?

Are you mean that I have to open the dash to check??

I looked behind the dashs, they looks the same, when the speedometer not working, I wonder if there is other wire of something, but there is not, they seem to be designed to assembled easily, those dashs work fine beside the speedometer, so I think there is other problem maybe.

How do you think about it?

Thanks

Joe

 

What does the speedometer do? Not move at all? Bounce around? The speedometer gear might be damaged...I forget where it's located though.... What year is your car? Your car might have a VSS (Vehicle Speed Sensor) instead of a speedometer gear...again not sure...but if the dash is from a year that used the gear and cable, and your car has the sensor instead, that might explain it. If your speedometer is cable and gear driven, might want to check the cable. They need to be lubed up I believe or they can stick and not work.

 

Most likely it's not your dash unit that's the problem. The Speedometer gets its signal from the ECM (computer) which gets it's signal directly from the VSS mounted on the side of the transmission. Most likely either your VSS went out or their is a short between the VSS and the ECM. That was the problem with my 92. What I did to eliminate the short (yes, I know it's not the BEST way to do it, but the easiest) was drill a hole in the trans tunnel, and ran wires directly from the VSS to the ECM. If I recall correctly, the colors are purple/yellow but I'd look that up to make sure. After that, my speedometer worked again.


BTW, i did this after forking out the $75 to replace my VSS.

 

You're kidding, right? That's exactly how a GM mechanic would fix the short! Sure you could've traced the whole damn wire out but man, life's too short for that kind of crap.

Just make sure you use a grommet or something so the metal doesn't cut thru the wire and cause another short!

 

You need the gauge unit I have. Caint really use it w/o a speedometer hook up

edit: Karl, you want me to take some good pics of the gauge cluster wiring before it goes inthe car? I have the rally gauges (read full gauges)

 

That is how I did it

Yes I did use something around the wires/hole to insulate it.

 

Thanks alot, btw, Is your wife a Chinese ?

YES!
Somedays I feel like it's an episode of "I Love Lucy"! I love her to death, she's such a wonderful woman & mother for our Son.

Where my dash is failing is
I have the wiring plug from the "gauges" dash.
I cut it off after I took out my Gauge package dash
From what I understand,
I need duplicate that "guage" dash plug wiring on my "idiot light" dash plug wiring for my "gauge package dash" to eventually work.

My true one question...
The Tach?
Will I have that one wire, already in my "idiot light" dash wiring harness? Or need I make one from the coil to inside the dash

Joe get abck to us.
Is your car a 1985?
I believe 1985 model year was last year for cable speedo.
Curious? What do your speedo numbers read?
Metric or US speed numbers?
Does the speedo stop at 85 MPH or go higher?