This is on my 98 SSE Bonneville with the Bose amplifier and automatic HVAC.
I just replaced the factory radio with a new pioneer headunit I have the wiring kit and hooked all that up and added a connector for the remote turn on so the bose amp works to power the speakers.
When I turn the car on with the new head unit the digital climate control its display just shows "--", but when I connect the factory unit it functions correctly.
My best guess is that the problem is from the Diagnostic Signal - E&C wire that now is not connected to the factory radio. (FSM Radio C2 - Pin 15 - Circuit No 835)
I'm not sure what I need to do to get it to turn on any suggestions?
Replaced radio no Climate control
- Phantom
- Posts like an LN3

- Posts: 485
- Joined: Thu May 22, 2008 8:52 am
- Year and Trim: 1998 Bonneville SSE
Re: Replaced radio no Climate control
Just to note I do not have a PAC unit for it yet.
Also I took some measurements of the wire in question.
Radio not connected:
5.6v Ignition off
4.4v Ignition run
4.8v Engine running
Stock radio connected:
7.25v Ignition off/run
8.6v Engine running fans on
Also I took some measurements of the wire in question.
Radio not connected:
5.6v Ignition off
4.4v Ignition run
4.8v Engine running
Stock radio connected:
7.25v Ignition off/run
8.6v Engine running fans on
- Phantom
- Posts like an LN3

- Posts: 485
- Joined: Thu May 22, 2008 8:52 am
- Year and Trim: 1998 Bonneville SSE
Re: Replaced radio no Climate control
I tried to trace the circuit in the stock HU with no success as the trace flips from one side of the PCB. I looks like the wire runs to a capacitor but it is hard to tell since there are 3 traces that go under the capacitor and i cant see under it.
If nothing is connected then the ECC does not function properly*, if I plug the stock radio back in it will have the dashes flash for a sec then start working.
* = The fans will turn on after the car gets up to temp but I cannot control it see the temp or use the defroster.
The only two wires not connected to anything now are pin 16 and 15
Pin 16 = steering wheel audio controls. (I believe that is the pin it is on or its 14 if it counts the other direction)
Pin 15 = Diagnostic Signal - Entertainment & Climate
The third pin on that side is a ground at pin 20 I added this pin and tied it into the ground even though it was not needed. (Note: function was the same when this ground was not connected.)
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I checked the wiring and it all seems fine each speaker is correct, power, switched, ground, and remote are all hooked up. I connected an insulated spade terminal to the remote wire to hook up the power antenna and have an easy point to connect the BOSE amp and add a second amp later.
I forgot to mention that I did not connect the orange and orange/white wires since my HU does not use the illumination and dim wires. Could that be a problem? I do not think that it would be a problem as I have not used those two wires when hooking up my 01,03 GP 93 Bonneville or 93 LeSaber that had ECC.
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Does any one have a 98 with ECC and the Bose system that has an after market HU? If so can you look at your harness for me?
If nothing is connected then the ECC does not function properly*, if I plug the stock radio back in it will have the dashes flash for a sec then start working.
* = The fans will turn on after the car gets up to temp but I cannot control it see the temp or use the defroster.
The only two wires not connected to anything now are pin 16 and 15
Pin 16 = steering wheel audio controls. (I believe that is the pin it is on or its 14 if it counts the other direction)
Pin 15 = Diagnostic Signal - Entertainment & Climate
The third pin on that side is a ground at pin 20 I added this pin and tied it into the ground even though it was not needed. (Note: function was the same when this ground was not connected.)
-----------------
I checked the wiring and it all seems fine each speaker is correct, power, switched, ground, and remote are all hooked up. I connected an insulated spade terminal to the remote wire to hook up the power antenna and have an easy point to connect the BOSE amp and add a second amp later.
I forgot to mention that I did not connect the orange and orange/white wires since my HU does not use the illumination and dim wires. Could that be a problem? I do not think that it would be a problem as I have not used those two wires when hooking up my 01,03 GP 93 Bonneville or 93 LeSaber that had ECC.
-----------------
Does any one have a 98 with ECC and the Bose system that has an after market HU? If so can you look at your harness for me?


