Jeff's DIY

Advice on doing your own diagnosis and repair

Advice from the book Can I Do It Myself?



Removing Door Panels

So your window or door locks quit working, or maybe you just want to install some speakers; but you can't figure out how to get into the door.
Well, it isn't because the designers wanted to trick you. The panels are designed for quick assembly. Yes, there are a couple big screws holding the door pull to the door, but much of the panel is actually held in by plastic fasteners. The fasteners look something like this

Typical panel fastener

and they slip into slots in the panel. The assembler then just slips the panel down onto the edge of the window opening and pushes the fasteners into holes in the inner door steel. Then he/she puts the few screws in and voila.

Another popular design is to have hooks built into the panel such that it hooks in as it slides down over the window opening. An example is shown in the photo below.

Typical door panel removal


So, how do you take the panel off? Reverse procedure!!

Find all the screws you can find and remove them. Also remove the window crank, if you have manual windows. A window crank may be held in by a clip behind it. You can remove the clip by fashioning a small hook out of a stiff paper clip to grab and pull the clip out. Here is a photo of what that looks like:

Window crank release technique


Some panel screws may be hidden under little caps. Carefully remove any caps that might have screws under them. Any caps on the panel may pull straight out with a little prying or they may have 2 or 3 tangs that you need to push in with your screwdriver as you pull the cover out. Lay out all of the screws and parts somewhere in a way that will help you remember how to put it back together.

Be sure to remove any trim parts above the panel that might prevent you from getting the panel up off of the window edge. For example, if the mirror access panel is in the way, it must be removed--not the mirror--just the access cover.

Once you have all of the screws out you can find, start prying gently at the edge of the panel until you can get your hand behind it.

Prying door panel carefully


See if you can find the plastic fasteners with your hand and pull out near the fastener to release it from the door, being careful not to damage the panel, as the panels are often weak enough to be damaged during this process. Go around the edge until you have released all of the fasteners. If the door is still held on by something, double-check for screws you may have missed or peek behind the panel with a flashlight to see what is holding it. Once the panel will swing out pivoting on the top edge, or if it is of the hook design in the photo above, pull it straight up about an inch to get it off the window edge. Don't pull it out yet, as you still need to disconnect the door lock, opener, and any cables before the panel is free from the door. Look carefully at how any of these things are attached and make a mental note of how they will go back together. Then unclip, unplug, and disconnect everything from the panel. Any connectors will have a catch that you will have to press to release the connection. Door lock actuators may come off with the panel or stay with the door. If they come off with the panel, you will need to disconnect the actuating rod, usually by unclipping the stay from the rod and pulling the rod out of the actuator.

Once the panel is off, there is usually a moisture barrier you also need to remove. If you only need access to one area, peel the barrier back. Otherwise, take it all off, but be careful not to rip it.

Now do your business inside the door and reverse these procedures to reinstall the door panel.

If your ultimate issue is the window motor, please see my window motor tip.


Power Window Motor Replacement

This job can be done by a good backyard mechanic, but a novice may have difficulty. If you get started and then get stuck, you're going to have your door apart for a while...
OK, so you've decided you are up for the challenge. Please make sure the problem isn't a fuse or relay that is more accessible before getting into the door. Let's go over a bit of the theory of operation to help you with that and troubleshooting the actual window motor and circuitry. The window motor itself is usually quite simple--it is getting to it that presents issues.
The motor is a simple DC armature with commutator and stator winding. It turns one direction for a given polarity and reverses with the opposite polarity. For this reason, the motor is isolated from ground, and the window switch has to be at least a double-pull-double-throw (DPDT) switch. Usually, the switch will pull up out of the door panel or is mounted on a smaller control panel that you can unscrew or pull up. In these cases, you can do a little troubleshooting without removing the door panel. If you have windows that will automatically go all the way down with one push, there is also a relay in the door, and the circuitry is much more complicated. That said, you can at least troubleshoot your switch without getting into the door; but, unless you're really good with electronics, you will need a diagram for the switch terminals and circuitry.

Troubleshoot the switch. You will need the switch and wiring diagram for this. With the switch pulled up out of its hole, wrap something around the wires to keep the connector from falling into the door and release the connector. If your motor was not working from the switch, try applying power directly from the battery to the connector to operate the motor. Be careful to get the right terminals, or you could fry the wiring in the door. If the motor will work with direct power, the problem is in the wiring or switch. Troubleshoot the switch with an ohmmeter. Also use a test light on the connector to check for power to the connector (with the key turned on). If there is no power to the connector, recheck the fuses and accessory or window relay. See my relay tip to check the relay.

OK, so you've decided you have to get into the door. Here we go...
If you haven't removed the door panel yet, see my door panel tip to accomplish that task.

If you're just trying to fix the relay in the door that makes the window go down on a single push, locate that relay and replace it.

If you're changing out the motor, read on.

Before removing the motor, see if you can isolate the 2 motor wires and jump power directly to the motor to see if it works. If the motor works with direct power, your problem is in the switch or wiring.

If the motor does not work, first disconnect the connector on the motor. If the window is down, try to raise it manually to make the job easier. Next, remove the mounting bolts or screws. The motor may be mounted with rivets. If so, carefully drill out the rivets-you will replace them with short bolts. Remove and replace the motor, making sure the gear engages the window mechanism; and reattach the motor connector. Test the system by hooking up the switch while the door panel is off.

If everything works, replace the moisture barrier and door panel.


Car Will Not Take Gas--Gas Station Pump Shuts Off

Are you having trouble filling your car up? This problem is usually caused by a failed vent valve. Not all cars have them; but, in those that do, the vent valve is used to seal off the evaporative emission control system while the computer is checking the system for leaks. The vent valve is designed to remain open until the computer starts a leak test. The computer commands it to close along with opening the purge valve to allow vapors to flow from the canister to create a vacuum in the fuel tank. If your tank is not venting, either the vent valve has failed closed or the canister or hose is clogged/not accepting vapors.

To repair, first locate the vent hose and valve. The hose is usually connected to the pump assembly on top of the tank and routed to the valve and canister. On most fuel injected cars, there are 3 hoses on the pump. One is the fuel line, one is a fuel return line from the fuel pressure regulator, and one is the vent/vapor line. The canister is usually near the tank but may be in the engine compartment in older vehicles. In those cases, there is rarely a vent valve at all, as a simple reed valve was used in those days.

An example of a vapor canister is shown below.

Typical charcoal canister


An independent purge valve may look like the pic below:

Stand-alone purge valve


Sometimes the vent hose is attached to the filler pipe rather than the tank. In any case, you are looking for a hose that goes from the top of the tank or the filler pipe and leads to a charcoal box or can. The vent valve may be mounted on or integral to the canister or it may be separate. If it is separate, it will have 2 hoses attached rather than just one--the second one going to the canister. In every case, the vent valve will have an electrical connector used by the computer to close it. In an emergency, you can remove the vent hose from the valve to allow the tank to fill/vent; however most states require a properly operating evaporative emission system, so be sure to repair the valve as soon as practical.

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