Unfortunately, finding a simple wiring diagram for just the blower motor circuit online is challenging. Full wiring diagrams for older vehicles are often part of a larger, subscription-based service offered by auto repair information providers like:
* AllDataDIY: This is a popular option for DIYers offering detailed repair information.
* Mitchell 1: Another reputable source for professional-level repair information.
* ChiltonDIY: Similar to AllData, offering comprehensive repair manuals.
These services usually require a paid subscription, but the investment is often worthwhile if you plan to tackle more repairs on your own.
How to troubleshoot without a diagram:
While a diagram helps, you can still diagnose this yourself with a multimeter:
1. Check the Blower Motor Resistor: This component controls the blower speeds. It's often located behind the glovebox or under the dash. Look for a burnt smell or signs of overheating. Testing its resistance with a multimeter (following the resistor's rating) will determine if it's faulty. This is the most common cause of intermittent blower operation.
2. Check the Blower Motor Switch: This is the control you use to select blower speeds. It's usually located on the center console. Testing the switch's continuity at each speed setting with a multimeter can identify a faulty switch.
3. Check the Blower Motor itself: Once you've eliminated the resistor and switch, inspect the blower motor for physical damage and listen for any unusual noises when you turn it on. You can also test the motor with 12V directly (with caution) to verify it functions.
4. Check the power and ground connections: Visually inspect the wiring harness for any breaks, corrosion, or loose connections at all the components (resistor, switch, motor). A multimeter can verify that 12V is reaching the blower motor at the correct time and that a good ground exists.
5. Check the relay (if you suspect it): Relays are usually found in the underhood fuse box or the interior fuse panel. Once you find the blower motor relay, you can check its operation by swapping it with another (identical) relay in the fuse box. If the problem switches, the relay is the likely culprit.
In short: Don't assume it's a relay until you've systematically checked the other components. The resistor is the most likely culprit for intermittent issues. The paid service manuals mentioned above will give you the specifics of where those components are located on your 1997 LeSabre and detail how to properly test them.
