Im trying to find out where the resistor to the control blower fan speed is located in a 2016 Peterbilt truck so i can replace it, the part # p93caa3100-01s

The heater motor speed reduction resistor assembly is generally placed in the heater air intake so the incoming air helps keep it cool - the resistor generates quite a lot of heat. In spite of this the resistor is generally a very reliable piece of equipment.

Most new vehicles have a one year warranty so if you have a problem the dealer should be fixing it.

Open glove box. Remove the screw around the lip (t20, iirc). Remove the glove box. Resistor should be visible looking down and to the right. Two screws hold it in place. Not sure on 2016 models but 14/15 did have a failure in the control head that caused no fan speed or just single speed issues. 2016 should still be covered by warranty. The control head is an expensive repair if the resistor is not at fault. I only mention this because resistors generally are reliable and don't fail for many years.

Hi,just food for thought,has he looked on the fan blower its self,hope this is where it is all the best.

talk with a service technician as there are resistors all over the vehicle
resistors to reduce 24 volts to 12 volts
resistors at the back of the instrument panel
resistors in the voltage regulator
resistor to control the blower fan speed
the number means nothing but what it is supposed to be part of to control voltage would be a very big help
post again as posts are not linked

I would replace the blower motor resistor first then see if that corrects this. The resistor is located next to the blower motor under the dash.

I don't even have a 2011 Peterbuilt! ;)
But as in many vehicles when the blower only works in high its due to a bad blower resistor. The resistor is in operation on slower speeds and the motor gets full power and bypasses the resistor on the high speed setting.

As for where it is on a Peterbuilt, again I don't o0wn one so I can't say for sure.
It should be located near the blower motor as it uses the fan blades air to keep it cool.

This may be just a blower motor (a/c fan) resistor issue. This resistor, depending on your vehicle is usually located near the blower motor. Remove the blower motor to locate it. This resistor controls fan speed, when they fail some or all fan speed may not work.

Hi!!
When the Blower Motor Resistor (controls blower speeds) goes bad, the blower motor works only on HIGH SPEED. REPLACE IT.
BLOWER MOTOR RESISTOR Removal & Installation

• Disconnect negative battery cable.
• Remove right lower instrument panel insulator panel.
• Disconnect blower resistor connector located behind right side of dash.
• Remove blower resistor screws and blower resistor.

To install, reverse removal procedure
Good Luck!! A HELPFUL - 4 THUMBS - rating for this solution would be greatly appreciated. Thank you for using FixYa!!

The blower motor fan is controlled by the blower motor resistor.Its the resistor which controls the fan on respective speed which you select.But if the resistor goes faulty,then it will not be able to set the required speed which you set for fan,so it works on high speed only. In this case you will have to replace the blower motor resistor. Check fog for the location of blower motor resistor location:--- see part number 8 in the diagram below.

The blower motor resistor is located next to blower motor under the dash.Its fitted with 2 screws and a wiring connector.You have to remove the screws and wiring connector and take the resistor out and place the new resistor in same position and connect the connector as well as screws. ------------------- this should help.Thanks.Helpmech.

The resistors are in circuit only on the lower fan speed settings.
On the highest speed setting, power is switched directly to the fan motor.
Check fan power supply fuses,
Check power is available to the fan when high speed selected.
If all above OK, apply power directly to the motor to verify fan motor runs- if it doesn't the motor may need replacement/repair.