Question:

The key-fob transmitter has stopped working on my '99 Corvette. I called my local dealer's service department, and they wanted more than $100 just to look at it. Is there any way I can repair the transmitter without going to the dealer? Also, how do I access the transmitter battery?

Locked-out Paul
Via the Internet

Answer:

There are three things that usually go wrong and prevent a transmitter from doing its job:

1. The transmitter may need to be resynchronized. Stand next to your Corvette and hold down both the Lock and Unlock buttons for approximately seven seconds. The horn will chirp, and you're done. If the horn doesn't chirp, the problem may be in the transmitter, so you'll need to move on to Step 2.

2. Now we need to try to match the transmitter to your car.

A. Turn the ignition key to the "On" position, but don't start the car.

B. Clear any warning messages on the DIC (Driver Information Center) by pressing RESET.

C. Press OPTIONS several times until you get the blank DIC page. Then press and hold RESET for two seconds.

D. When you see the DIC message "FOB RETRAINING," push RESET once. The message "HOLD LK+UNLK 1ST FOB" will be displayed.

E. Press and hold the LOCK and UNLOCK buttons on the transmitter for 15 seconds.

F. If successful, the DIC will display "FOB LEARNED." Now a prompt for the second transmitter will be displayed.

G. Repeat Steps E. and F. for each transmitter you have (up to three).

Remove the key from the ignition.

To replace the battery in the key fob, simply pry the two halves of the transmitter apart (Image 1). You will see a round battery (CR2450), which can be found at any parts store (Image 2). When replacing the battery, check for broken prongs, as this is a common failure.

These steps should help. If not, the next question is, Does the PKE (Passive Keyless Entry) lamp light when the key is first turned to the "On" position? This is a system self-test and will indicate if the PKE receiver is defective or just in "Sleep" mode.

When you shake some fobs, you'll hear a rattle. The sound is caused by a tiny gold bearing in a small cylinder, which "wakes up" the fob when movement is detected. Otherwise, the fob would be on all the time, draining the battery.

If the ball bearing becomes dirty, its movement can be impeded, making it much more difficult to wake the fob. In extreme cases, the fob may not reactivate at all.

It's sometimes possible to clean the inside of a fob using a moisture-free dust remover. This procedure is similar to cleaning the mouse on your home computer. Remember: This is an electrical unit and therefore should not be oiled, so choose your cleaning agents with care.

If the PKE light does not illuminate at all when entering the programming mode, you may have a bad PKE receiver. Check the PKE fuse and the radio fuse, both of which are associated with PKE operation. If these look to be OK, the receiver likely has failed. Unfortunately, the receiver is located behind the DIC in the dash, making it difficult to access.

The last potential cause of PKE problems is a malfunctioning door switch. If one or both of the switches aren't reporting the correct status to the CCM (Central Control Module), the PKE system can lose its ability to lock and unlock the doors.

To determine whether the switches are working correctly, simply start the car, close the door, turn the radio on, and let the engine run for approximately 30 seconds. Next, turn the car off, remove the key, open the door, and look to see if the "Door Ajar" light illuminates on the dash. Also note whether the radio goes off when the door is opened. If not, the door switches could be defective. If the door switches do turn out to be bad, they can be replaced through their existing holes, without taking the whole door apart.Good luck.

Question:

I'm the new owner of an '80 Corvette and need to replace the battery. Where is it, and how do I remove it?

Hugh
Via the Internet

Answer:

C3 batteries are difficult to get to and even more difficult to jump start, as they're mounted in the rear storage compartment behind the driver seat. To remove the battery, first make sure the driver seat is moved all the way forward. Always disconnect the battery starting with the ground terminal and then the positive terminal. If you disconnect the positive first, there's a possibility you'll accidentally contact metal with the wrench. If the ground is still connected, you could damage your car-and possibly yourself.

After removing the battery cables, loosen the single fastener to remove the hold-down bracket. Slide the battery slightly rearward, as this will release it from the additional fixed clip in the front. Lift the battery straight up for removal. Once the new battery is installed, make sure the battery-door seal is in good condition. This door seal prevents any gases from leaking into the interior compartment.

While we're on the subject, let's cover how to remove the battery from a C4. In an '84-'96 model, the battery is located in the lower access panel behind the driver-side wheel. To replace it, remove the inner fender panel behind the front tire. Next, open the driver-side door. On the lower rocker panel, you'll see some small Torx screws. Remove the first two (closest to the front). Once these are out, you'll see a 7mm bolt on the bottom of the rocker molding, almost directly under the front doorjamb. Remove this bolt and lower the front half of your Corvette's rocker molding.

With that done, you'll see two 10mm bolts. Remove both of them, followed by the battery's side cover. Now you can disconnect the battery cables. (Remember to remove the negative cable first.) Remove the 13mm bolt and retainer that hold the battery to the battery tray, then lift out the battery itself.

Question:

First off, I want to say that I love the "Tech Corner" column. It helps us weekend warriors with our Corvette-project questions. Here's mine: I recently purchased a '97 Vette, and I've noticed an engine feedback noise through the factory radio. The noise is coming through the speakers on all stations, even when I have a tape in the player. It's become so annoying that I usually turn off the radio so I don't have to listen to it. What do you suggest?

MattVia the Internet

Answer:

It sounds like you're getting some Electro-magnetic Radio Frequency Interference (EMI or RFI). EMI/RFI can cause unwanted signals on a radio receiver or, in extreme cases, even result in driveability problems such as intermittent misfiring or a dramatic loss of power. Such problems arise when engine-management computers receive signals that have been altered by interference.

There are a few things that can cause this problem. The first thing to check is if there are any aftermarket electrical accessories installed in the car. Some non-factory components can cause the noise you're describing. To determine if a particular aftermarket component is your problem, unplug each item, one at a time, and see if the noise goes away.

The next thing to look for is non-factory ignition-system equipment. Aftermarket spark-plug wires are one of the more common offenders. Also, make sure your battery terminals are torqued to 11 lb-ft, and verify that the positive post of the battery is not leaking or loose. A loose battery connection can cause an array of electrical issues. The alternator connections should also be checked to ensure they're not loose.

If all of the above checks out, I'd recommend that a noise-suppression capacitor be installed into the main battery source that goes into your radio. The capacitor can be purchased from your local dealer or even Radio Shack. This should reduce or eliminate the condition.

Question:

I was just reading your recent article on the C4 headlight fix. It's applicable to the '89-'96 Corvette, but I have an '85 model, and the motor is completely different. Mine has two wheels, and I haven't been able to remove them. I'd appreciate any help you can give me.

JimVia the Internet

Answer:

You're correct: The headlamp motors on the '84-'87 Corvettes have a two-gear system that rotates the lamps. The problem is that the motors use nylon gears to rotate the heavy lamp assemblies, and the these gears eventually strip out where they contact a metal worm gear. This was a common failure on C4 Vettes, so Chevrolet redesigned the headlamp motor for the '88 model year.

The replacement procedure for the headlamp-motor gears is not very difficult and can be performed in about 45 minutes. The gear kits are available from most Corvette suppliers for less than $80.

1. First, remove the headlamp-housing retaining nut. Looking into the headlamp housing, toward the motor, and you'll see the 13mm retaining nut.

2. Next, remove the headlamp-motor wires from the headlamp frame. They're held by a metal retaining clip located in the corner of the frame. Now that the clip is removed, unplug the headlamp connector near the front side-marker light.

3. On the bottom of the headlamp motor, there's a knob with a locking strap. Remove the strap and rotate the knob until the headlamp is in a position where you can remove the side screw from headlamp-housing cover. Separate the cover from the housing, taking care not to scratch the paint.

4. There's a small bracket that attaches the headlamp motor to the hood hinge. Remove the carriage bolt between the bracket and the hinge. Next, remove the bolts that hold the headlamp motor to the headlamp frame. Now the motor can be removed.

5. Place the headlamp motor on a work bench and pull the wire clip away from the locking knob. Then, remove the Phillips-head screws that hold the motor housing together. At this point, you can separate the two components by gently prying them apart.

6. Using a pair of pliers, pull the large gear out of the motor housing. Note the placement of the small washers on each of the gear shafts; these will need to be reinstalled in the same location when the gears are replaced. Now, pull up on the gear; it will slip out. Wipe any crusty grease and old gear debris from the housing, apply a generous amount of lithium grease to the entire gear assembly, and install the new replacement gear in the motor housing in the same position from which it was removed.

7. To remove the small gear, you'll need to lock the shaft in a vise and use a brass punch and hammer to remove the pin that attaches the gear to the shaft. Once the pin is removed, you can take the shaft out of the vise and use pliers to remove the gear from the housing. Install the new replacement gear on the shaft, then put it back into the vise to reinstall the locking pin. Be sure to apply a generous amount of lithium grease to the gear teeth.

8. Before bolting the two halves back together, apply a small amount of silicone sealant to one of the halves to prevent water from entering and damaging the motor. Reassemble everything in the opposite order in which it was removed.

Hope this helps.

Got a question for our Tech Corner expert? Just jot it down on a paper towel or a lightly soiled shop rag and send it to us at VETTE Magazine, Attn: Tech Corner, 9036 Brittany Way, Tampa, FL 33619. Alternatively, you can submit your question via the Web, by emailing it to us at vette@sourceinterlink.com. Be sure to put "Tech Corner" in the subject line.

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