wheelo90

I did some testing and I think I need a new KSB sensor that plugs into the intake manifold.
I have power going to it, but no power coming out of it, and the temp outside was in the 40's. The truck had not been running all day so I know the motor was cold.
Any advice on what to do or how to take care of my problems. Or where can I find a new sensor at? And is it going to cost me an arm and a leg?

Thanks,
Wheelo

wheelo90

Alright I will try and call Cummins tonight after school

Tuckerdee

Yes, Cummins is the place. $30-$40 I think. I replaced mine a few months ago.

edwinsmith

Is the sensor a simple switch or is it an electronic device like a thermistor that connects to a control module which sends power to the KSB?

I tested my KSB solenoid byt taking it out and connecting it to 12V the plunger comes out slowly on mine because it is a wax type. It's not difficult to get out and test it. I'm not sure about the sensor. Hopefully somebody else will chime in before you go spending money for nothing.

Edwin

Tuckerdee

The sensor is just a thermostatic switch in the top of the intake manifold. Although they are opposite depending on which type of KSB you have. They get 12v directly from the top of the shutdown solenoid. I have the solenoid type KSB, so the switch is closed (on) when cold and open (off) when hot. I think the switches for the wax type KSB work opposite...but I'm not sure.

edwinsmith

I think the wax type works the same it's just slower to react. Thanks for the clarification.

Edwin

bgilbert

These rarely fail. Why do you want to replace?

wheelo90

I want to replace it because I can get power to it but no power out of it when the truck has sat for 2 days in 40 * temps. I done all the testing, the wire to the shutdown soliniod, the wire from the soliniod to the sensor and I have 12 volts. But from the sensor to the KSB on the pump, nothing. I tested the wire comming out of the sensor probably 4 inches from the sensor itself(the wires arent broken)
Anybody got any advice bfore I drop the money and buy one?
Wheelo

wannadiesel

Nope, sounds broke to me. As long as the air temp in the manifold is under 90 degrees you should have power across that switch.

wheelo90

I know it is definately broke now. I ran a wire from the positive terminal down to the KSB on the pump and brought the truck up from an idle, and wow. Was it noisy, it kind of had the "COLD RATTLE" to it. The sound that you get on those dreaded cold winter days when you fire her up in the morning.
Now I know it is the switch, and not the thing on the pump that is wrong. Thanks everyone,

Wheelo

bgilbert

So you're looking for that cold start advance then? Can't live without it?

torquefan

The early type of switch found on the non-intercooled trucks rarely ever failed. The later one on the intercooled trucks was a common failure item. Its Dodge part number is 4713521, but I think they are starting to go obsolete.

wheelo90

Just looking for the sensor that screws into the intake on the truck. Thanks for the part number, going to check it out!

Wheelo

bgilbert

I still don't see the need for it...??? Put the money in the fuel tank I say .

wannadiesel

It's a nice feature for those who like their trucks to be a little more civilized. It doesn't hurt anything to fix it.