Cruise control intermittent & 5VDC trigger accessory same

[Jonas007]

So I have a little satellite radio from sirius custom mounted in my dash, and instead of powering it off the lighter (which both looked ridiculous, and doesn't power off when you turn off the car), I wired it into a 5VDC line that is some sort of accessory wire since it turns on and off with the car. This worked fine for a long time, but now my satellite radio stopped powering up, sort of…it’s intermittent and I’m not entirely sure why.

1) Driving to work Friday, no radio

2) Driving home Friday, no radio

3) Stopped at rexall, started again for the 30 second drive home, radio works

4) Saturday morning no radio

5) Sunday morning, radio starts fine

6) Today, no radio until 10 minutes into my drive, then just lights up

The connection and splice are definitely not loose, it looks like the 5VDC is disappearing from some other car issue.

Strangely (and this has been an issue for a long while), my cruise control active (ready but not engaged) button has always been an issue, sometimes you start the car and the green indicator on the dash won’t appear. Pull the key and start again and its fine. I’ve noticed whenever the radio isn’t working neither is that button, but I can’t yet tie them together conclusively…

Car is an 02 996 C2, any thoughts on what to check? I've seen past topics where the rear brake light affected the cruise, but mine seems fine.

[logray]

If it were me, I would splice back together whatever wire you leeched off of in the first place (solder).

Then run new wires to the fuse box area, and wire a new 12v socket there or hard wire it into an "add a fuse" in a fuse position that is unused and only turns on with the key (or you can buy one of those piggy back add a fuse links and hook up to a slot that is already populated but can handle the addtl load of the sirus, i.e. radio fuse). Be sure to use and select a short ground cable, tie it into the dash frame for example. Don't run an excessively long ground cable.

From there, monitor the crusie control problem (perhaps the wiring you did is somewhow related).

Sample add a fuse, just a couple bux at your local auto parts store:

Edited April 10, 2012 by logray

[RFM]

Never connect accessories to a 5 volt wiring, it's the CAN-BUS wiring. Strange and unexplained failures will occur. Repair everything ASAP in their original state.

[JFP in PA]

Never connect accessories to a 5 volt wiring, it's the CAN-BUS wiring. Strange and unexplained failures will occur. Repair everything ASAP in their original state.

+1 on this, you really do not want to get involved with CAN-BUS headaches...................

[RFM]

Indeed most European cars run 5 volt on CAN-BUS and SIGNAL wiring's. Therefor testing with a BULB and/or LET no longer applicable, a good quality multi/volt meter (such as FLUKE) is recommended.

[Jonas007]

Update 1: It turns out the cruise is separate from the radio issue, as yesterday the cruise was working fine all day, but the radio would not power up. Strangely, it seems the past two days whenever I start the car after 7pm, the sirius lights up, but in the morning it does not. Probably just a strange coincidence, but very odd that it only likes the evening ;)

I will rewire and heatshrink wrap the splices to seal up any weirdness I may have caused. The reason I need a 5V source instead of 12V though is because the output on the original sirius adapter is 5VDC, if I run a 12V source to something looking for a 5V, it will most certainly fry either in short order or in the medium to long term.

Does anyone know of a safe "empty" 5V source in the fuse box that I could draw from?

[logray]

I'm guessing some of your electrical gremlins could be due to the wiring you've done. It is also possible the strange symptoms stem from a faulty ignition switch, or could be unrelated. Again, I would try to return everything as close to stock as possible, and then proceed with adding a 12 volt socket correctly. Then proceed from there to monitor what problems the car still exhibits, and proceed troubleshooting from there. Eliminate as many variables as you can so you aren't troubleshooting several diffiernt issues simulataneously.

The only "usable power" you should be using in this car is 12 volts. The entire fuse bus runs off of 12 volts if I'm not mistaken.

You should locate the original sirius 12v to 5v dc "cig lighter" converter (or buy a replacement if you have to), and use that per my advice above to wire in a new 12v socket somewhere under the dash., drawing power from an unused accessory fuse position or piggy back off of another fuse using the appropriate adapter.