Well i fixed the instrument cluster.''One of the wires had no power going to it.Now when u shut of the engine the door locks go nuts,locking and unlocking till I open the door and then all is good again.Also the Speedo is not working and I the ABS light is on + I dont think the O/D is not working.

Any idea on where to start.

 

ok, to start have you tried seeing if there is any codes? with the ABS light on, i'm guessing you have a code thrown. if you don't have a scan tool, swing into an auto zone / advanced auto and see if they can get a quick reading for you.

with the speedo not working, that problem might be something dealing with the VSS (Vehicle Speed Sensor) located on the read diff.

is the OD light flashing at all on the shifter, or is it just not working when you push the button? this could have something to do with your OSS (Output Speed Sensor) located on the tail shaft of the transmission.

as for the door locks acting weird, i have no clue.

something else to start to look at is your wiring, is there any wires that are rubbing, maybe causing a short, batt terminals clean, any thing running rough ( ran into this a while back, and it ended up being a couple bad spark plug boots causing an intermittent ground connection)

keep us posted as to what you turn up!

 

Also check your shifter wires, they have been known to chafe and strip back and cause weird symptoms.

 

Thanks for your help guys............got to pick up a code reader at the weekend but I did change the VSS tonight and no change..........I'l keep you posted.

neil

 

Plugged a code reader in today and it says vehicle speed sensor malfunction,but I changed that last week.
Any ideas?

 

what was the code? there are 3 different speed sensors, VSS (vehicle speed sensor at rear of vehicle on the diff), OSS (output speed sensor, at the rear of the tail shaft of the transmission, or output shaft sensor), and the TSS (turbine speed sensor, on the front of the transmission that measures converter turbine speed)

if your getting a P0720 code that is a generic code for "something in the speed sensor circuit isn't working". you often get this code when there is an interruption in the circuit some how. meaning there could be a ground fault (loose connection), there could be an AC signal at some point, meaning there isn't a constant current flow to one of the circuits (can be caused by bad diode in alternator, or faulty sensor), OR you could be getting an extra ground signal from some where else (so far the most common is a faulty spark plug boot, you get an arc from the coil causing a ground signal interruption).....

 

It was P0500

 

What should I look for next ?

 

X2 on the faulty boot. I go through this every time a cop goes bad, 3 times now when they go bad, it puts out the 0720 code. Install new boots and maybe springs, and it should clear up. The first time I changed the OSS, but then realized later I didn't have to. Oh well, live and learn on these trucks. That's what these forums are for.

 

FWIW, My speedo and stopped working and my ABS light stayed on after I installed my HID's. I found that I mounted the transformer on the passenger side to close to some sensor. I moved it about 6 inches and all is good again.