Most Likely Culprits:
* Wiper Motor Resistor: The wiper motor usually has a resistor pack built into it or as a separate component. This resistor reduces the voltage going to the motor for low speed. If this resistor fails (often by burning out), you'll lose low speed but high speed will still work (it bypasses the resistor).
* Wiring to the Resistor: A break or short in the wiring leading to the resistor or from the resistor to the motor will also interrupt low speed. This could be a broken wire, a corroded connection, or a poor solder joint.
* Wiper Motor itself (less likely): While less common, a problem within the motor's internal components could also cause this issue. However, if the high speed works, this is less suspect.
Troubleshooting Steps:
1. Check the Fuses: Start with the simple stuff. Check your owner's manual to locate the fuse(s) related to the wipers and make sure they're intact.
2. Inspect the Wiper Motor and Wiring:
* Visual Inspection: Locate the wiper motor (usually under the hood, near the firewall). Carefully examine all wiring connected to it, looking for any obvious damage, corrosion, or loose connections. Pay particular attention to the wires going to the low-speed circuit (if you can identify them).
* Continuity Test (requires multimeter): If you have a multimeter, you can test the continuity of the wires leading to the resistor and the resistor itself. Disconnect the wires from the motor and resistor before testing. Lack of continuity indicates a broken wire. Check the resistor's resistance value according to the Jeep's wiring diagram (finding one online might be challenging but helpful). A significantly higher or lower resistance than expected indicates a faulty resistor.
3. Locate and Test the Resistor:
* Finding the Resistor: The location of the resistor varies depending on the year and model. It might be integrated into the wiper motor itself, or it could be a separate component located somewhere in the wiring harness under the hood or dashboard. Consult a wiring diagram for your specific Jeep model to find its location.
* Testing the Resistor: If you find it, you can test it with a multimeter for continuity. Again, a wiring diagram would help understand the specific resistance values to expect.
Repair Options:
* Replace the Wiper Motor Resistor: This is often the most effective solution. You can usually purchase a replacement resistor pack or entire wiper motor assembly from auto parts stores.
* Repair Wiring: If you find a broken or corroded wire, you'll need to repair or replace the affected section of wiring. This might involve soldering, crimping, or even splicing in new wire.
* Replace the Wiper Motor: As a last resort, if the motor itself is faulty, you'll have to replace the entire wiper motor assembly.
Important Notes:
* Wiring Diagram: A wiring diagram specific to your 1997 Jeep TJ 2.5L is highly recommended. This will help you identify the components, their connections, and troubleshoot more effectively. You can find these diagrams online (often on Jeep forums) or through a repair manual.
* Safety: Disconnect the negative battery terminal before working on any electrical components in your vehicle.
* Professional Help: If you're not comfortable working with car electrical systems, it's best to take your Jeep to a qualified mechanic.
By systematically following these steps, you should be able to pinpoint the cause of your low-speed wiper malfunction and get your wipers working properly again. Remember to always prioritize safety when working on your vehicle's electrical system.
