Your description – steering feeling normal then becoming loose – points to several potential problems, none of which involve a column-mounted switch:
* Power Steering Pump Failure: The most likely culprit. A failing pump may initially provide adequate pressure but then weaken as it wears, leading to the intermittent loose steering.
* Low Power Steering Fluid: Check your power steering fluid level immediately. Low fluid will cause exactly this symptom. If low, add fluid of the correct type (consult your owner's manual). However, low fluid is usually a *symptom* of a leak or failing pump, not the root cause.
* Leaking Power Steering Hose or Rack and Pinion: A leak in any part of the hydraulic system will reduce pressure and make steering loose. Inspect all hoses and the rack and pinion for leaks.
* Power Steering Rack and Pinion Problems: The rack and pinion itself might be worn or damaged internally, causing inconsistent assistance.
* Loose Belt: A slipping or loose serpentine belt (which drives the power steering pump) can cause intermittent power steering assistance.
How to diagnose:
1. Check Power Steering Fluid: This is the absolute first step. Look for leaks around the pump, hoses, and rack and pinion while checking the fluid level.
2. Inspect Belts: Ensure the serpentine belt is tight and in good condition. A visual inspection will usually suffice.
3. Listen for Noises: A whining or groaning sound from the power steering pump is a classic sign of pump failure.
4. Professional Inspection: If the problem persists after checking fluid and belts, it's crucial to take your truck to a mechanic or qualified automotive professional. Diagnosing power steering issues requires specialized tools and knowledge. They can pinpoint the exact source of the problem and provide the correct repair.
Changing the Pump (if needed): Replacing the power steering pump is a moderately complex job that requires mechanical skills. It involves draining fluid, disconnecting hoses, removing the pump, installing the new pump, refilling with fluid, and bleeding the system. A repair manual specific to your 1997 Chevy truck is highly recommended if you attempt this yourself. This is *not* a beginner-level repair.
