Votage drop from blower motor

[Spencer]

Hey everyone, new here. Hoping someone can help me out a little. Ive had several of these trucks but this issue has me stumped. First of all, i have replace all of my grounds and power wires in the engine bay. Power was replaced with 1 gauge and grounds were replace with 4 gauge. I also ran a 4 gauge wire directly off the back of the alternator to the batter. This has been very irritating and id like to get this figured out before i install my electric fans and single 10 sub. Battery test 12.5 volts not running and around 14 idling with no load. There doesnt seem to be an issue until the blower motor is on high. Going to the road is fine its when its to running temp and coming to stop. It doesnt kill the truck but it definately dips down pretty low. Ive checked almost every ground i can find. Any advice or input on experiences with this will be greatly appreciated!!

 

[df2x4]

Probably just the motor going bad and putting a ton of resistance in the circuit. I had the same issue with the original blower in my Suburban and just ignored it for a while, eventually it burnt up the motor and the resistor. Replaced both and it's been fine ever since with no major voltage drop.

 

[east302]

Same thing here, new blower resolved it.

At idle, compare alternator/battery voltage with and without the blower on high.


Sent from my iPhone using Tapatalk

 

[GMCTRUCKS]

Let me tell you how my 1993 GMC truck got me my trucks relays in back of the glove box we’re making a clicking sound and my speedo was going crazy and at times it felt as if it had a bad miss and last the Trans felt as if was going into limp mode well it turned out that the negative cable was a tad loose at the battery.

 

[90halfton]

You could use an ohmmeter across the motor leads and see if it's reading a high resistance. Also can check the current flow while it's running.

 

[laidbackbigun]

Why did you replace with only 4 ga wire? i believe like all the others your blower motor is going out, but the 4 ga just isn't going to help a ton once you have a system in there and fans. I have 1/0 gauge for everything and i still feel lacking, maybe i'm just jealous of other mens cable size?

 

[jasons99hoe]

usually good to use same size cable all way around. ground same as hot. im sure what you did wont cause a problem but when you see electrical its same size. i think the guys are right about the blower motor.

 

[laidbackbigun]

I mean don't get me wrong anything is a help over the crappy couple of runs the factory gives but i think i might have gone just a big bigger than 4 ga and tried to do the same as your 1 ga power run.