High resistance

[zim2704]

When the ignition is off and testing the grounds I'm getting anywhere from 0 to .3 ohms, which is good enough in my book. The problem is that after I turn the ignition on, motor not running, the resistance jumps to 3.5 to 5 ohms.

Does anyone have an idea why the resistance rises so significantly and what can be done to fix it? I believe this is what's causing random electrical issues throughout the truck.

1999 K1500
Ext. Cab 4x4 w/ 5.7ltr

 

[GoToGuy]

Try cleaning every ground point . There all listed and drawings of locations. What about listing what random issues you have? And where are testing for this check?

 

[zim2704]

A few of the issues I've had are vibrating fuel gauge, melting blower motor connections, failing actuators and melting connections on climate control harness.

 

[AK49BWL]

Vibrating fuel gauge can be remedied by some grease in the air core motor in the cluster. It's normal on 98+ trucks tho because of the way the gauge is activated - the PCM sends a pulse-width-modulated signal to the gauge, which is basically a continuous full-voltage on-off-on-off cycle that simulates a certain voltage to the gauge to show proper fuel level.

Melting blower motor connectors can indicate a bad ground, OR a failing blower motor that is pulling excessive current... But is yet another commonality on these trucks.

Failing actuators, how are they failing? Yet again a common issue, stripped or cracked gears in the actuators, or in the case of the vent mode actuator, the two arms that control the defrost and front vents have lost their retainers and springs, or they've gotten stuck.

Clean your grounds, and make sure the ground straps that run between the engine and frame and body are still intact. If they aren't, no better time to upgrade!

 

[Erik the Awful]

When the ignition is off and testing the grounds I'm getting anywhere from 0 to .3 ohms, which is good enough in my book. The problem is that after I turn the ignition on, motor not running, the resistance jumps to 3.5 to 5 ohms.

You can't measure resistance on a live circuit. Your meter measures resistance by sending a small current through the wire. If you want to check a live circuit, you're better off measuring voltage drop.