Identifying Your Transfer Case Control:
* Electronic (Most Likely): Your Blazer likely has an electronic transfer case. This means a small electric motor is used to shift the transfer case. The module controlling this motor is what needs replacement. You'll usually find it mounted near the transfer case itself, sometimes under the dash, or possibly even near the engine bay's fuse box. It'll be a relatively small electronic component with wiring harnesses connected.
* Cable-Controlled (Less Likely): If your transfer case is cable-controlled, the "module" is actually the cable itself and the shift linkage. A failing cable usually requires replacing the entire cable assembly, not just a module. You'll see a physical cable running from your shift lever to the transfer case.
Replacing an Electronic TCCM (Most Common Scenario):
1. Disconnect the Battery: This is the most important step to prevent electrical shorts and damage. Disconnect both negative and positive terminals.
2. Locate the TCCM: This is the trickiest part. The location varies slightly by year and trim level. Common locations include:
* Under the dash: Look near the steering column or under the instrument panel.
* Near the transfer case: This is a more likely location. Look underneath the vehicle near the transfer case.
* Engine bay: In some instances, it might be near the fuse box.
3. Disconnect the Wiring Harness: Carefully unplug the electrical connector(s) from the TCCM. Take photos or make notes of how the connectors are plugged in to ensure proper reassembly.
4. Remove the TCCM: Depending on its mounting, you might need a few tools. This could involve removing fasteners (bolts, screws) or possibly unclipping it.
5. Install the New TCCM: Mount the new TCCM in the same location as the old one. Ensure it's securely fastened.
6. Reconnect the Wiring Harness: Plug in the electrical connectors, making sure they are correctly seated and locked.
7. Reconnect the Battery: Reconnect the battery terminals.
8. Test the Transfer Case: Engage and disengage the 4WD system to confirm proper operation.
Important Considerations:
* Diagnosis: Before buying a replacement TCCM, it's highly recommended to have the system properly diagnosed. A faulty TCCM might be the problem, but other issues (wiring, transfer case itself, etc.) could also cause 4WD problems. A scan tool capable of reading transmission/transfer case codes is very helpful.
* Part Number: Ensure you get the correct TCCM part number for your specific 1994 Chevy S-10 Blazer. The year, engine size, and trim level will impact this.
* Professional Help: If you're not comfortable working under your vehicle or with automotive electrical systems, it's best to take it to a qualified mechanic. Incorrect installation could cause further damage.
* Cable-Controlled Replacement: If you have a cable-controlled system and the cable is faulty, replacing the cable is a more involved job requiring access to the transfer case linkage.
This information provides a general guideline. Always consult a repair manual specific to your 1994 Chevy S-10 Blazer for detailed instructions and diagrams relevant to your vehicle. A Haynes or Chilton manual can be a significant help.
