Who has a 1991.5 and a scanner.I'm looking to see if the prnd21 changes on the scanner reading as shifter is changing positions.I know it does on the other years 90/92/93.

 

I have never seen or experienced this, but I would think as long as the truck has an ECM then it should be as you stated.

 

I am not 100% sure but I think it only knows if it in park or neutral. It don't really know what gear it is in other than than. Best was I can explain is P_N___ will be displayed if it is in park or neutral. _R_D21 will be displayed in any other gear. I can check for sure tomorrow when I have my scanner with me.

 

Moparnut thats just what i need to know is yours a 1991.5 truck with the od module behind glove box.The reason for this question is i have had no od since i put a new engine in my truck,Ive checked everything and the only thing that comes up is that computer doesnt know its in forward gears and not letting od or cruise work.that value on my scanner never changes and i have seen other 1st gens change but mine is the only 91.5 i have worked on.

 

Mine is a 91.5 but I don't know what od module you are talking about behind the glove box. The only thing behind mine is wa black box for the aha brakes.

 

Behind the glove box on right hand side there is a module specific to 91.5 for od not used on any other years thats what makes that mid year special.

 

there is a second gray module tucked under behind the glove box on my truck. I always wondered what it was for... The big black one is for the RW ABS, but like I said, I got a smaller gray one back there too iirc.

 

Ya if you look in the tech section under 91.5 wiring diagrams you'll find it.

 

I dont see anything on my truck besides the rw abs box that is black and unplugged in my truck. What page in the diagram is the box you are talking about? Do you have a pic of it?

 

Ok I think I found it in the diagram it says it is mounted on the right side support is that the one you are talking about? I can't find it on my truck what does it look like?

 

The box is about the size of a smoke pack with 6 wires coming from it.but what I'm needing to know is the scanner says when shift lever is changing positions.

 

It may see Park (Neutral saftey switch) Reverse (back up lights) and Neutral (neutral saftey switch).

Why are you looking?

 

My od is not working,I've gone through the wiring,od module,temp sensors,tps and had computer sent away for testing and still no od.Yes i have a switch jumped to od wire and it work's.the only thing i can see that's funny now is the reading on my scanner for prnd21 never changes when shifter is moved in to differrent positions I've seen it change on the other 1st gens i have scanned.I can't find anyone with a 91.5 in my city to confirm that it does change.

 

I will scan mine tonight and let u know for sure if it changes you may have a bad neutral safety switch will it start in any gears other than park or neutral?

 

No saftey neutral switch is new as all the sensors have been replaced and new od module.All the wiring has been checked and computer sent away to be checked.Reverse lights work so does only starting in park and neutral.