Blower Relay Failure

[JPMACH1]

01-Ranger 3.0L
Blower motor relay keeps burning out. Have replaced 5-relays in the last 6-weeks.
Resistor is New. Pigtail is New. Replaced resistor thru the years but now only lasting about a week and dies.
Relay is in PDB under hood. Temps are Outrageous in Texas this year. Are under hood temps the problem..?
Anybody ever had this problem. Resistor is simple fix but Relay is the problem. 1 terminal connection is overheating.
I have a New Blower motor just haven't installed it yet. Worth a Shot.

 

[Snoranger]

Overheated connection means high current draw. High resistance/ high load can cause that. Some things that can cause it:
Bad blower motor
Bad connection at blower
Bad connection at relay

 

[RonD]

2001 Blower motor relay needs to a for sure 40amp relay, not 30amp

But fuse 16 in engine bay fuse box is a 40amp fuse, and it should BLOW if amps get close to 40amps, make sure someone didn't replace it with a 50amp fuse

Blower motor should only draw 15-20amps on HIGH
However electric motors will have a spike amp draw on start up

And yes I would say its time to replace blower motor, if the speed resistors have been failing and now the Relay as well


The relay is connected directly to the Fuse and to the blower motor and supplies the motor with 12volts

The Resistor Block provides the Blower motor's Ground
It has 3 resistor coils in series
Low speed provides the ground thru all 3 resistors
Med Low provides the ground thru 2 resistors
Med High provides the ground thru 1 resistor
High is a direct ground, no resistors

All electrical systems need a "circuit"(circle) of power flow
In a DC system the 12v wire and the ground wire need to pass the same AMPs, people often focus on the 12v side but the ground side has to pass the same power or there is no "circuit"(circle)
So you can control a light bulb(dimmer) OR a blower motor by limiting the ground the same as limiting the 12volts, there is no difference in control

In vehicles car makers usually use the Ground wire as the control because its safer
If a 12v control wire should short to ground you get a blown fuse as best result but a burnt wire and maybe a fire as worst case
If a Ground control wire shorts to ground a device comes on, thats it, no blown fuse no fires, so safer