How to Add an Aux Audio Input to 2005 Toyota Corolla Stereo

iPod Touch playing over aux audio cable in 2005 Toyota Corolla

Connecting your iPod Touch or other MP3 player to your car can be a real problem. RF car adapters often have poor sound quality, tape adapters have poor quality and require a tape deck (which a lot of newer cars don't have, including 9th generation Toyota Corollas which ran from 2003 to 2008), and Aux audio input adapter kits can cost upwards of $75. Presented here is an alternative method to hook your iPod up to your car; you can manually add an aux input to your car stereo yourself. A 2005 Toyota Corolla with a single disk cd player is used as the example, but this technique works for many types of stereos.

Difficulty:

Moderately Challenging

Instructions

things you'll need:

• Flat head screw driver
• Philips screw driver
• Socket wrench
• Soldering iron and solder
• Long stereo headphone cable (extension cables have wires that are easier to solder)

1. • 1
     Lower shifter cover

     Section 1 (Steps 1-3), Remove the Toyota Corolla Stereo:
     Insert a flat screw driver under the plastic base of the shifter to lift it up. You don't need to disconnect the cigarette lighter wires, and don't mess with the shifter itself. This piece simply needs to move out of the way a little to get the other pieces of panel out.

   • 2
     Center fan speed know hides screw

     Remove the center control knob (fan speed) from the instrument panel and undo the screw hiding behind it. The whole instrument panel snaps out as shown in the picture. Again, don't worry about disconnecting wires they are long enough to move the panel out of the way to get to the stereo.

   • 3
     Stereo mounting screws

     Behind the control panel underneath the stereo are four 10 mm screws that mount the stereo to the dash. Remove these and pull the stereo and front air vents out. Carefully unsnap the antenna and speaker/power connectors from the back of the stereo. Slide the vent assembly off of the stereo. Be careful not to scratch the instrument panel while removing it.

   • 4
     Back of stereo assembly

     Section 2 (Steps 4-11), Disassemble Stereo and Solder on Aux Input for iPod:
     The stereo assembly consists of a CD player and radio with amplifier inside of a metal frame that has brackets attached for placement in the car.

   • 5
     Faceplate ribbon cables

     Begin disassembly of stereo by removing the eight bolts holding two mounting brackets (marked L and R). The face plate of the stereo snaps off; carefully disconnect the two ribbon cables that interface the face plate with the stereo body.

   • 6

     Remove the small screws of the top, left side, right side and bottom of the metal box assembly. The top slides off first followed by the sides and bottom.

   • 7

     Remove the CD player by taking out the two small screws from the front (where the face plate was). There are "CD" markings by them. Carefully disconnect the ribbon cable that interfaces the CD player and stereo body.

   • 8

     Think about the way the CD player interfaces with the rest of the stereo. The cable connecting the two must control the CD player and relay the CD audio out. Look for clues on the CD player circuit board to find which points soldered to the connector provide these functions. For the 2005 Toyota Corolla with a single disk CD player (A51813, Model Number: 816120-02430) the cable from the CD player has 14 conductors (or ways) and each is labeled on the CD circuit board as follows: 1 = n/a, 2 = SW1, 3 = n/a, 4 = n/a, 5 = n/a, 6 = RESET, 7 = n/a, 8 = SIMO, 9 = SOMI, 10 = SCKM, 11 = SW3, 12 = LCH (for left channel), 13 = ACOM (for audio common), and 14 = RCH (for right channel).

   • 9
     CD player connected to stereo assembly

     Cut the headphone extension cable (keep the side with the male headphone plug) and strip the three wires. On the cable I used, black was the audio common (ground) and red and white were right and left channels respectively. The ribbon that connects the CD player to the stereo body plugs into a bulky connector that is soldered to the stereo main board with large pins, the perfect place to solder to. The cable conductors are labeled on the CD player, so follow the path of the LCH, RCH, and ACOM along the cable to the main board connector to find the correct pins as labeled in the diagram below.

   • 10
     Solder locations shown here in red

     Carefully solder the RCH, LCH, and ground headphone wires to the appropriate pins shown in red. For best results, strip the wires so that only a very small amount of conductor is exposed (you only need a tiny bit, this will help prevent short-circuits), and use the solder already on the board (simply heat the pin until the original solder begins to melt and push the wire in). Take your time, be careful. You really don't want to accidentally solder together multiple pins, and you don't want to block the ribbon cable you must plug back into the connector.

   • 11
     Aux cable taped in place

     Tape or hot glue the headphone (now Aux input cable) in place.

   • 12

     Section 3 (Steps 12-17), Reassembly and Install:
     Replace the CD player ribbon cable, and secure the player to the stereo body via the two small screws in the front. Replace the bottom plate and side plate opposite of where you fastened the aux input cable.

   • 13
     Route the aux inoput cable through the back

     Route the cable out the back of the stereo assembly as shown, and replace the remaining side and top plate. Plug in the face plate ribbon cables and snap the face plate in place.

   • 14

     Replace the left and right mounting brackets.

   • 15

     Position the stereo close to where it will be mounted and route the aux input cable down through the back of the dash to where you can reach the end by the floor. Slide the stereo almost into place, and reconnect the antenna, power, and speaker cables. Make sure that you don't scratch your control panel or pinch wires. Before you put your panels back together make sure that your new input works. Inserting an old CD upside down will leave the stereo reading audio out from your new aux input, my stereo shows "Error 1" when this happens. No problem. Plug the jack into your iPod or other MP3 player and let her rip! Note: having a CD inserted the regular way works too, the iPod signal overpowers the CD... I just like the upside down CD trick better.

   • 16

     Slide the stereo and front vents in place and mount with four 10 mm screws. Snap the instrument panel in place. Replace screw under fan speed knob and replace knob. Snap shifter bottom cover into place.

   • 17

     You are ready to roll! Position your new aux input for your iPod touch or whatever you have in a convenient place.

Tips & Warnings

• If you are trying to do this to a stereo other than the one shown, research your make and model first. This should be done on systems with a separate CD player board.