Procedure to Install 94-99 Bonneville Stereo Into a 92-93 Model Year Bonneville
This project will teach you how to install the much more common 94-99 Bonneville Stereo, into the 92-93 models. It is difficult to find a stock CD player for a 92-93 Bonneville, but 94-99 CD players are much more plentiful. This procedure assumes you have basic electrical repair experience
If you have automatic climate control, you will lose the dimming capability of the VF display on the head unit. In order to retain the dimming capability you must purchase a 1994 automatic climate control head unit, which has self-contained dimming capabilities. This procedure will also cover the installation and electrical modifications to install the new head unit, if desired.
- Mounting brackets
The mounting brackets on the right side of the radio are the same. No modifications are necessary.
There should be a mounting bracket on the bottom of the radio to grip the lower track as you push it back. If not, you must remove the bracket from your old radio, and cut the top piece off so that it will fit your new radio. Mount it over the bolt, in a similar fashion to your old stereo.
The left side of the radio presents a problem because there is a plastic peg that sticks out from the dashboard. Drill a hole slightly larger than the peg into the radio mounting bracket so that the bracket will slip over the peg and fit flush on the dashboard. The top mounting screw is located in the same place as the old radio.
- Radio wiring harnesses
Here is a diagram of the main 20-pin wiring harness, facing the wiring harness and not the back of the radio.
11 12 13 14 15 16 17 18 19 20
1 2 3 4 5 6 7 8 9 10
The existing wiring harness will likely not fit into the radio because of some extra tabs. You can get the correct wiring harness from a junkyard, and splice it into the existing wiring. You can also purchase female and male wiring harnesses at most radio stores, which will allow you to retain the old wiring harness by simply plugging it into the new female end, and then splicing the new male end onto the female end. However, most aftermarket wiring harnesses are missing the top left quadrant (11-16). This quadrant is where the steering wheel controls will plug in. If you don’t have this harness, and you want to retain steering wheel or diagnostic capability, then you will have to get one, either from the junkyard or from the dealer.
Connections 1-10 and 17-20 are exactly the same for the new radio. Splice these wires together in the correct locations.
However, the wires that went to the auxiliary connector on the other side of the radio (1 to 3, depending on the options your car has) now have to be routed to the new wiring harness in the upper left quadrant (11-16).
This is how the old auxiliary wiring harness appears:
7 Dark Green – Data Line Input
6 Light Green – Steering Wheel Controls Input
5
4
3 Purple/White – Special Climate Control VF Display Dimming Signal Output
2
1
The No. 7 wire must be spliced to pin No. 15 on the new radio. This is not critical, but it allows scan tools to communicate with the radio.
The No. 6 wire must be spliced to pin No. 13 on the new radio. This is your steering wheel control signal wire to the radio.
If you have a No. 3 wire, you will no longer be able to use it, since the newer radios do not develop the special VF display dimming signal. For this reason you will lose the dimming capability of the electronic climate control display. You can cut the end of the wire off, and disregard it.
- Automatic Climate Control
In order to retain dimming capability of the electronic climate control display, you must purchase a unit that has self-contained dimming capability. The correct replacement unit is the 1994 climate control head (GM Part No. 16201124). In order to integrate this control head you have to complete some simple wiring changes.
The unique identifier of the 94 automatic climate control head is the “AUTO” button. It has the word “AUTO” in orange with an orange borderline around it. The 88-93 models have the word “AUTO” in black inside an orange box.
This is how the old wiring harness appears (facing the wiring harness, not the back of the climate control unit):
12 11 10 9 8 7 6 5 4 3 2 1
A B C D E F G H J K L M
Here are the configurations for the old and new, modified wiring. Pins A thru M are not used.
PinOldModified
1GreyGrey
2Purple/White-
3--
4Dark Green (1)Dark Green (2)
5Dark Green (2)Dark Green (1)
6--
7--
8--
9BlackBlack
10-NEW (Hot with parking lamps on)
11BrownBrown
12--
You must remove the purple/white wire. You can remove the wires from the harness by removing the upper clip on the back of the harness, and then by inserting a paper clip in the front underneath the pin, and then by pulling the wire out the back. Save the wire and pin to use in slot 10.
After you remove the purple/white wire, you must switch the four and five wires so that the data will be transferred properly from the programmer and back to the radio. You can do this easily by switching the two wires through the back of the harness.
You must add the “parking lamps on” signal to slot 10. To do this you need to splice a wire from the pin in slot 10 on the climate control (reuse the purple/white wire pin and wire) to the wire at pin No. 6 on the radio. The No. 6 radio pin wire is dark green on the 93. Beware; aftermarket wiring harnesses may use different colored wires. This modification will provide the new signal to the 94 electronic climate control to signal the VF display to become dim, and to use its internal processor to determine the brightness.
After completing the wiring harness modifications, you can install the 1994 electronic climate control head unit. There are no mounting modifications that need to be made.