I had an iSimple TranzIt RF modulator installed into my H3 2 weeks ago at Best Buy to play my iPhone through my factory nav. Its connected to an accessory power line but when I turn the ignition off.. the modulator switches off. The big deal is that the volume has to be up a bit louder, plus I tend to turn it up a bit as well so when I turn off the ignition there is a blaring of static. The modulator has a separate power switch on it so that you can turn it off if you need to. Is there a way to get it tied into the retained accessory line so it stays going until I turn the truck off?

The guy at Best Buy said that I needed to do a relay and a door switch. Seems like a lot more work than necessary isn't it?

 

If you could post the schematic, that would help a ton! But shooting from the hip, all you would need to do is connect it to a continuous power source. Take a $10 analog voltmeter(found at most stores that carry any sort of auto parts/accessories), and find a power source that stays on when your key is not in the ignition. I wouldn't recommend this without first knowing what kind of load the unit will put on the battery. Meaning, it may drain your battery when your car is turned off overnight.

 

Sorry for double post, couldn't figure out how to edit.

I think I understand the logic of what the best buy fellow is telling you. He wants you to put in a door switch because this is when our factory systems "turn off" once we have actually turned the ignition off. If it were me, I would simply use a "quick connect" type splice, and connect the modulators power source to the same power cable supplied to your car radio that shuts off when you open the door. The reason for the relay, is so your modulator doesn't power back on once you shut the door.
Post a schematic!

 

A note on the orange wire to the factory radio.
It is always hot. I connected sirius radio and at the same time I connected my CB power to the orange. CB always on.
I found an old post here with schematics and pics on hooking up the sirius radio and the guy said to use the orange.
If I could do it again (which I will tear in again and redo), need to find another power.

The aux power wires under the steering column are also always hot.
I had originally had my CB connected to the power at the rear wiper switch. But whenever I keyed the mic, the rear wipers turned on for a cycle.

 

You can either go to the fuse box under the hood for a power source, otherwise the accessory wire in the ignition harness under the dash might be another source to test. The R.A.P. going to your radio should be coming from the fuse box under the hood most likely though.

 

Use a multi-meter and check the empty fuse slots in the fuse box under the hood. When you find one, (I did), that turns on/off with the ignition, THAT will operate with the retained power. Tap into THAT empty fuse and run the wire into the cabin by pushing it through the same grommet that the hood release cable comes through the firewall.