Weird steering problem 99 k1500 suburban

[outlaw55]

Maybe someone can help me with this one. I have here a 99 4x4 suburban. Your driving down the road and the power steering just goes out. You pull over and turn the truck off, let it sit a couple minutes and restart it, and you have power steering again. Repeat, repeat, repeat. Sometimes it shuts off after 5 minutes of driving, sometimes hours. We changed out the pump and it still has the same problem. It just shuts off. If someone has had this same issue and has corrected it or knows how to correct it, I would very much appreciate it.

[1997SierraSLT]

here is a detailed post regarding my experiences with the steering system on these vehicles.

 

http://www.gm-trucks.com/forums/topic/154921-97-gmc-sierra-erratic-steering/

 

Note, your power steering pump has an electrical solenoid screwed into the back of it connected to a two-wire harness. This solenoid operates a plunger inside of the power steering pump to either increase or decrease line pressure to the power steering gearbox. It is part of the VSS system.

 

If you disconnect this harness from the power steering pump, you should have full power assist. If not, I suspect you have a failing solenoid.

[outlaw55]

I've heard of unplugging it, I'm actually going to try it tomorrow and see. It's an aggravating problem. Thanks for the information, I will put it to use. Thanks again

[1997SierraSLT]

I don't recommend leaving the power steering pump solenoid unplugged. You'll have full power assist at ANY speed. This can be very dangerous when buzzing down the road at any prominent speed. You can steer with simply a touch of your fingertip.

[outlaw55]

I'm open to suggestions, believe me I don't want to get in a wreck. I'm just trying to figure it out. Should I just replace the solenoid and see if it fixes it? I hate to just throw parts at it.

[1997SierraSLT]

This solenoid is just one part of the VSS electrical system. Most often, the VSS sensor mounted on the steering column (under the dash) is the culprit. The ECM sends a specified electrical voltage to this potentiometer and it in turn varies the electrical voltage going back to the ECM based on degree of rotation at the steering wheel. The ECM in turn calculates this degree of rotation at the steering wheel, your road speed, and adjusts the voltage to the solenoid accordingly. The slower you drive, the more power assist you have. As you speed up, the rate of power assist decreases.

 

I found this article.....very interesting! Worth a shot and it's fairly inexpensive.

http://www.pacificp.com/forum/viewtopic.php?t=10246

[outlaw55]

I think we're going to try that bypass kit rather than just unplug it. That sounds like the best bet. Hopefully it will eliminate future problems all together. Thanks for the info. I can't have it unsafe at highway speeds.

[1997SierraSLT]

Outlaw55,

If you opt for the GM retrofit kit to bypass the EVO/VSS system, please repost to let us know the results. Thanks!

[John Boelte]

Before VSS, vehicles had full power steering at any speed.