Chrysler Repair: Resistor Block, dodge ram 1500, intake plenum

Question
My air/ heat only work on high. I have a 2000 Dodge Ram 1500. Someone suggested it might be the resistor block. We have been trying to find a picture of this so we know what we are looking for. One told us it might be by passenger side firewall the other told us behind glove box. Any ideas on where it is and what it looks like and if it is not this then what? Patty

Answer
Hi Patty,
The resistor block is indeed the suspect. I don't have any experience with the truck line nor do I have a manual. But based on the car lines I would suggest looking in the air intake plenum under the front windshield where the outside air for the cabin ventilation is taken in. Usually there is a mesh screen covering the channel and the air is ducted toward an intake at the far passenger side of the plenum channel then goes thru the fire wall to the ventilation console.
In the general area of that passenger end of the channel you are likely to see a set of resistors that are located in the air flow stream so as to keep them cool, that is the resistor block.  The plate on which they are mounted can either be attached to the fire wall side of the plenum (therefor in the upper right side of the firewall or it will be mounted on the cabin side of the plenum behind the glove box, just underneath the windshield. There is a an electrical plug for the block, usually with about 5 wires, and 2 screws hold the block in place. So, open the hood and look at the right hand upper corner (where right means the passenger side) and if not seeing it there then you may have to remove the glove box to see behind it (or look up from the floor to see behind the glove box) to see if you see a plug and rectangular panel with 2 screws. If you can look into the air intake plenum and with a flashlight and see the resistors, then you will know where to look for the mounting plate. You don't have to go inside the plenum to get the block out, but you do have to locate it and then search for the mounting plate on either side of the firewall as I have described.
If you don't find such a block, then a more modern design, used in the LH and Cirrus cars, is to place the block in the air handling console proper under the dash on the right hand end adjacent to the blower motor, again so the air blows over the resistors to keep them from melting. Again there is a plug and screws secure it to the console
That is my best information. You could also go to a Dodge truck dealer and ask at the parts department to show you their computer based drawings that show where the resistor block is located. You may have to buy it there anyhow, but check the price elsewhere before going to the dealer to see if the price is really different.
Roland