Ed Hahn's Muth Signal Mirror Install Page

On 7 September 2002, I installed the Muth Signal Mirror kit on my 2002 Chevy Avalanche. This kit, which was a present from my lovely wife, is intended to provide a turn signal that is visible to drivers in the blind spot of the vehicle. Since the Avalanche is a long vehicle, with no side signal lights, I thought that this would be a good safety improvement for the truck.

Of course, it is only effective if one uses one's turn signals. But everyone uses their turn signals, right? Right???

DISCLAIMER: I am posting these photos for illustrative purposes only. Muth recommends that a professional do the installation. If for any reason you decided to TAKE RESPONSIBILITY and do the install yourself, I applaud you. However, DO NOT hold me responsible if anything happens during your installation. No warranty is implied. BTW, I am not affiliated with Muth in any way, other than as a customer.

This is picture of the kit as it comes from Muth. As you can see, it is pretty simple - two replacement mirror glasses and the wiring and splices necessary to wire the blinkers into the truck's signalling system.

This is what the back of the replacement mirror looks like. As you can see, there is a heating element which takes up about 3/4ths of the space behind the glass, and an LED package on the outer 1/4. The mounting puck is attached to the back of the heating element. Note that this glass is very similar to the OEM glass, with the exception that it is not framed in plastic. Also note that they sell a (cheaper) version of the kit without heating elements for other trucks without heated mirrors. HOWEVER, they do not sell a version which retains the optional driver's side self-dimming feature. Since my truck doesn't have that option package, there were no downsides to my installation.

Here's where the nitty-gritty starts. The instructions are very well written, with only a couple of things not mentioned (I'll mention them here). Anyway, you start by pulling off the triangular trim from the inside of the door panel. It is held in place by two spring clips, and pulls straight off. Foam is stuffed into the cavity behind the trim, which is where the mirror mounting bolts and wiring live.

The second trim piece to come off is on the door handle - same deal with the spring clips (two), just pry with your fingers it straight out at the rear of the trim piece; the front has a flange which fits under the forward part of the opening.

Here's the third piece of trim - the door control panel. Two spring clips again, on the inner side. Pry with your fingers under the inner edge of the control (you'll leave the clips in the door panel - use needlenose pliers later to get them out.) Once you have it loose, reach in and disconnect the three connectors on the bottom of the control panel.

That's all you need to remove before taking the rest of the door panel off. Note the two hex-head screws labelled in the photo above - remove these screws and the door panel will come off by lifting on the door handle and pulling up and away VERY GENTLY.

Here's the inside of the door. BEFORE REMOVING THE DOOR PANEL COMPLETELY, disconnect the DOOR LIGHT and speaker TWEETER CONNECTOR labelled in red above. Once these are removed, the panel should fall away completely, and leave you with the sight above.

The Light Blue labels are other items of interest on the inside of the door. The Green arrows are slots for the "hooks" on the door panel.

Here's what the inside of the door panel looks like. Note the Door Light and Tweeter Connectors that you had to disconnect. The Green arrows are the hooks which you will insert into the slots when it comes time to button up.

Once you have the door apart, it's a snap to unbolt the mirror and disconnect the mirror wiring. [Note that you'll see left and right mirrors in the next few picture sequences - sorry about that!] Once removed, you will follow the directions and pry the mounting puck on the OEM mirror glass apart, gently, from several different angles before pulling it up. Despite the warnings in the instructions, this part isn't that difficult. Reuse the foam gasket which comes with the OEM mirrors. Once the mirror is removed, you'll route the wires from the inside of the mirror, through the wire conduit in the base, to the mounting base of the mirror.

Taking the replacement glass from the kit, first attach the blinker connector and the mirror heat contacts to the back of the glass, and then orient the glass itself onto the mounting puck. Gently but firmly press on the glass OVER THE TOP of where the mounting puck is. You should hear a few snaps as the mounting puck snaps back together.

Here's what a mirror assembly looks like when it's back together.

The challenge is now to route the wires into the body. THIS IS BY FAR THE MOST DIFFICULT PART OF THE JOB, but only takes patience and perhaps a bit of skin off your knuckles. When putting the mirror back on the truck, route the wires through the hole in the door first (duh). Then you can feed the wire down through the inside of the door.

This is a closeup of the front part of the door panel, by the hinge. You can see that the wires have been dropped through the panel into the inside of the door. At this point, it will become necessary to carefully peel up the plastic sheet at the lower front corner. Once the sheet has been peeled up, you can dislodge the plastic tab which holds the door wiring grommet to the door. Route the wire out the hole and then carefully replace the plastic sheet to its original state. Press on the plastic sheet to make sure it sticks and forms a reasonably tight seal against the door structure.

At this point, you also need to remove the kick panels from the driver or passenger side footwell. First, pull up the plastic trim on the door sill, then pull the kick panel straight back toward the rear of the truck. The kick panel is held on by two large metal clips. You will need to gently bend the driver's side panel to get it to come loose from the hood latch - but the piece is designed to take it.

Once the kick panel is removed, you will need to dislodge the body side grommet, leaving the gooseneck conduit hanging as in the photo above.

Once you have the gooseneck hanging free, you need to pull the signal wiring through it. This can be done with a long screwdriver - feed it through the gooseneck as shown (carefully - don't force the blade of the screwdriver through any of the existing wiring insulation.) Once it is through, tape the end of the wire to the end of the screwdriver, and gently pull it back through. Once it is through, you can pull the slack through the gooseneck, and then feed the wire through the grommet hole in the body.

After the wire is inside the truck, you can just replace the grommets on the gooseneck into their respective holes.

Route the wires over toward the drivers side footwell, so you can splice and terminate it with the appropriate control signals.

This part I was not able to complete according to the directions - the brief wording in the instructions on how to locate the turn signal wires from the bundle under the steering column really isn't sufficient without a detailed wiring diagram to reference. I cheated and chose to route some wires from the front turn signals back into the truck body - but I don't necessarily recommend that you follow my lead.

Well, once I was able to find the correct wires from the turn signal up front, spliced them up according to the instructions, and grounded the black wires, I was ready to test. Success!

Putting the door back together was simple - just reverse the steps that you took disassembling it. Make sure you get all the "hooks" on the inside of the door panel aligned with the "slots" on the door structure, and also make sure that you have the door lock slider aligned with the lock handle. No rattles or other noise should be apparent upon reassembly.

The LED package is aimed to be brightest at a car in the blind spot. You can see the relative brightness from this position in the photo above, compared against the view from the driver's seat below.

From the driver's seat, the lights are barely visible - good as a "telltale" on whether the LEDs are lighting properly, but not distracting.

All in all, I thought this was a very worthwhile job. If you are confident working on cars and trucks, I would recommend considering a do-it-yourself install.

My overall evaluation of the kit is positive. If there were anything I would change, it would be to improve the instructions for locating the turn signal wires inside the truck. Otherwise, I think it is a high-quality product and a straightforward installation. I am also impressed by the simplicity of Chevy's door design - it is clearly designed to be easily assembled and worked on.

If you have any questions, please let me know.