Welcome back for the second part of our Passive Keyless Entry (PKE) system operation-and-diagnostics overview for '93-'96 Corvettes. This month we'll cover the component location, PKE diagnostics, and how to repair the PKE receiver instead of replacing it.
Let's review how the system works. When the system is in the passive mode, the PKE receiver (located in the vehicle) senses the transmitter in your key fob and automatically locks or unlocks the doors as you walk toward or away from the vehicle. If this isn't happening, and you've exhausted all the steps in last month's column, you'll need to remove the PKE receiver for examination.
Removing the PKE Receiver
The PKE receiver can only be accessed by removing the upper dash panel. The following steps will take you through this process.
1. First, remove the negative battery cable.
2. Next, remove all three air-vent outlets. This will expose two small Torx-head screws inside each outlet. Remove these.
3. There are more fasteners hidden under the fuse panel. Detach the fuse-box cover, then locate and remove the three hex-head screws that retain the side panel.
4. Behind the side panel is a hex-head screw for the lower knee panel and dashpad. Remove it.
5. Behind the passenger vents are three hex nuts that hold the lower dashpad in place. Remove these retainers and pop off (but don't completely remove) the lower dashpad. This will allow you to access the upper-dash-pad tabs.
6. Behind the center vent are two hex-head screws holding the upper dashpad and center trim. One is located on the left, holding the dashpad, and one is on the right, holding the center trim. Remove these screws and pop out the center trim about 4 inches.
7. Behind the driver's vent is one hex-head screw holding the dashpad. Remove this.
8. Next, pop off the defroster-vent trim in the center of the dash; take care not to damage the light sensor, which is attached. Removing the defroster vent will expose two Torx screws that are attached to the dashpad. Remove these.
9. Once all the screws are removed, carefully lift up on the dashpad and pull back to release the rear dash pins from the dash-pad reinforcement frame. The entire upper dash should come out with minimal effort. If it doesn't, go back and make sure all the hidden fasteners have been removed. Some dashpads will have random spots of adhesive holding the edges in place. These glued dashes will take a little more time and patience to remove but shouldn't give you too much trouble.
10. Next, remove the instrument cluster.
11. Once the instrument cluster has been removed, look under the center A/C-vent tube, directly behind the A/C control head in the center of the dash. Here you will see two boxes. The top box is the tone-generator (chime) module, which is held in place with Velcro. You'll need to remove this module to access the PKE receiver.
12. The PKE receiver is located directly under the tone generator. The PKE receiver is also held in place with either Velcro or spring clips on the sides. Now comes the tricky part. The PKE module can only be removed in the direction of the passenger side—and it won't go easily. You'll need to tug and tweak until you can manipulate the unit out.
13. The part number for the receiver is the same for all '93-'96 Corvettes (PN 10261112) As is the case with most items for the C4, Chevrolet has discontinued it.
Checking the Fuses
The first thing to do when working with anything that may be controlled by a fuse is to test all of the related fuses with a test light. Start by turning the key to the On position. There are two places to probe on the back side of each fuse; probe them with a test light and continue this process for every fuse (Image A). If the test light doesn't light on both sides, that fuse is most likely blown. If the test light doesn't light on either side of the fuse, you'll need to look in the owner's manual to see what that circuit feeds. Certain circuits may require that you activate something to illuminate the test light—for example, by turning on the headlamp switch.
Some key fuses on C4 Corvettes are:
&bull #40 BATT 5A (provides constant power to the PKE module)
&bull #26 PKE 5A (provides 12 volts when the ignition switch is in Run position)
&bull #42 POWER LOCK (provides voltage to the indicator bulb and power-door-lock relays in the module)