Ok, I did a whole bunch of work to my '07 990 SD recently and I'm having a major problem now. Primary symptom is that when I turn on the key, the lights, indicators and horn work but the instrument cluster doesn't cycle or show any lights as is normal on startup and the starter doesn't engage. It's like the main computer isn't working or something of the sort, but I'm hoping its a lot more simple than that. Here's the breakdown of everything I did:
1. Major cleaning of the harness and battery box under the oil reservoir. The PO apparently thought it was fine to just let oil drain onto everything. I used no water or water-based products during this process - only engine degreaser and brake cleaner. I disconnected all the connections and thoroughly cleaned and inspected them and reconnected everything. All the plugs are unique, so switching things around couldn't have happened. I checked the main fuse and that power is getting past the main relay there.
2. SAS removal and Rottweiler intake install. I was very meticulous here, had no leftover parts, and double checked all the connections more than once.
3. PowerCommanderV install. Again, very meticulous, found everything just as the instructions said, and it was a straightforward process. After I experienced this issue, I uninstalled all the connections to check to see if the Powercomander was part of the issue, and had no luck. Same symptoms.
4. Installed Cyclops LED taillights and headlights. Can't imagine this would have caused anything, but I checked the connections behind the light fairing to no avail.
A couple other points: This project has gone on for the past couple weeks as time allowed so I don't know exactly when the problem would have cropped up. But I wouldn't have noticed it before because with the tank off I wouldn't have tried to start it. I'm wondering if turning on the key with part of the harness disconnected can cause problems, because there was a lot of that. I also diagnosed a short to ground in the rear brake taillight switch, but the front brake triggers the light fine, even when the real brake is depressed so it seems there is sufficient isolation so as not to be a problem.
Any thought on where to start troubleshooting this? I noticed the ECU is difficult to get to - especially the plugs and I wasn't mucking around in that area anyway. All fuses have been checked and although the seat box was totally removed at on point the harness and relays are reinstalled well. I wiggled wires with the key on with no luck, hoping to find a bad wire somewhere.
1. Major cleaning of the harness and battery box under the oil reservoir. The PO apparently thought it was fine to just let oil drain onto everything. I used no water or water-based products during this process - only engine degreaser and brake cleaner. I disconnected all the connections and thoroughly cleaned and inspected them and reconnected everything. All the plugs are unique, so switching things around couldn't have happened. I checked the main fuse and that power is getting past the main relay there.
2. SAS removal and Rottweiler intake install. I was very meticulous here, had no leftover parts, and double checked all the connections more than once.
3. PowerCommanderV install. Again, very meticulous, found everything just as the instructions said, and it was a straightforward process. After I experienced this issue, I uninstalled all the connections to check to see if the Powercomander was part of the issue, and had no luck. Same symptoms.
4. Installed Cyclops LED taillights and headlights. Can't imagine this would have caused anything, but I checked the connections behind the light fairing to no avail.
A couple other points: This project has gone on for the past couple weeks as time allowed so I don't know exactly when the problem would have cropped up. But I wouldn't have noticed it before because with the tank off I wouldn't have tried to start it. I'm wondering if turning on the key with part of the harness disconnected can cause problems, because there was a lot of that. I also diagnosed a short to ground in the rear brake taillight switch, but the front brake triggers the light fine, even when the real brake is depressed so it seems there is sufficient isolation so as not to be a problem.
Any thought on where to start troubleshooting this? I noticed the ECU is difficult to get to - especially the plugs and I wasn't mucking around in that area anyway. All fuses have been checked and although the seat box was totally removed at on point the harness and relays are reinstalled well. I wiggled wires with the key on with no luck, hoping to find a bad wire somewhere.
