I'm new here and need a little help with my truck, I have a 91' 5 speed 4x4 CTD and my speedometer is not working, somebody told me it might be the crank position sensor, or something like that, I am open for suggestions. The local parts store does not list a speed sensor for the 5speed, just a 4speed auto, so I dunno what the deal is.

Also my pre-heaters are not comming on and niether is the wait-to-start light. I checked the selonoids and they are getting power from the battery and from the key and ground, but they are not clicking. If I jump around them the lights dim like the heater grid is coming on and all, I think just the selonoids are bad but not just wondering if anybody has had similar problems and could let me know if it could be anything else before I go get two more seloniods. Where would be a good place to find them cheap too, or could I just use a regular starter seloniod?


Thanks
Chris

 

The speedo is probably the Vehicle Speed Sensor. Any decent auto parts store can get it.

The grid heater relays are ground switched. Did you check the ground during cold start conditions? If you have power and ground, then the fault must be the relays. You can't use a Ford starter solenoid due to the fact that the relays are ground switched. You can get the relays from Grainger or an HVAC supply house, the part number is in the "tech facts" section of this site. I saw that Advance Auto Parts lists them as a "glow plug relay" as well.

 

I did not know that it was ground switched, but I did have ground with the key on and the truck cold, now that I know it is ground switched I will check that agian cause I was mainly looking to see if the hot was switched. I also called my local advanced and they didn't have anything for it I even tried "glow plug relay" I will try the dealer and NAPA today and see if I can find them.

BTW, I see on your signature you have a 3200 governor spring, where do ya get them at? All I can find them for is 94+ 12 valves, or will the 94+ 12 valve springs work?

Thanks for the help
Chris

 

call up PDR for the governor spring, its different than the 94+ trucks, its not listed on there site but they have them.

www.piersdiesel.com

 

Thanks for the info, I looked on there before but didn't see them, I'll give them a call since they have em'.


Thanks
Chris

 

Dodge's part # for the Speed Sensor to the Speedometer is #5252438, and set me back $71.60 a few weeks ago...(looking at the receipt now)
A 91 uses a two peice speed sensor unit that is mounted on the drivers side of the tranny tail fin. Check to make sure the wiring harness isn't loose or dirty, a little dielectric grease in the connector can fix the problem sometimes.
The sensor breaks down into two seperate parts, a "generator" (for lack of a better term) and a sending unit. The part # above is for the sending unit.
Mine was loose, then I overtightened it and broke it..fortunatly it is easy to replace, tho not cheap.....
There was a thread somewhere on here that had pictures of the two units and some testing procedures for them, ya might try searching the forum and see if ya can find it.
If not I will get a pic of it for you if you need it, or ask some of the senior guys here, they are GREAT help...

 

Thanks I just got off the phone with the local *********** and that was the price he told me. I did a search on here and came up with it being pretty consistant that they get dirty and quit so I might try that first before I spend $71 and it was just dirty. This site is cool, I never new there was so many gen I's out there, and all the mods available for them!!!


Chris

 

Ive tried electronic connection cleaner , not much luck ,maybe didnt hit the right one yet.
Seems all the connectors are a problem with dirt and moisture. Got to love these old trucks though!
Claude

 

Here's an update, after some further testing and knowing that they are ground switched I found I can get the relays and grid to work, just not like it is supposed to by itself without jumping the relays. Is there a thermostat that tells them how long to stay on and when to work or something? For the time being I will probably just hook up a ground wire to the relays on a switch and operate them manually since I need them this time of year, although she did start right up this morning in 20 degree weather!


Chris

 

If the truck is intercooled the PCM runs the grids. If it is non-intercooled there is an electronic box that runs them. The temp sensor is in the intake manifold, it's the one towards the front. You're not even getting a bulb check, though, so something is not right with the control circuit. I wish I could help you further but I don't have wiring info on the '91's.

If you hot wire the grids, use a momentary pushbutton. If you forget them they will fry themselves.

 

Yea, I just hot wired them so I would have them when I need them, I would still like to get them to work like they are supposed to, but till I get some money saved up this willl be okay, and if I need a new PCM then I will just leave them hot wired. BTW it is intercooled.

Thanks
Chris