dpower$

I have a strange situation I was wondering if anyone else has had or can explain. I have an early '86 that sits most of the time. It has an aftermarket stereo that has never given me any trouble. Returning from OCIC in Denver the radio would very intermittently shut off and immediatly power up again. it seemed to be caused when hitting a bump. I recently took the car to a stereo shop to rewire, replace, whatever to get the radio to work properly. As the memory functions remained when it powered off/on, I assumed that I had a bad connection at the key-on wire to the radio. After about 2 hrs the shop called to tell me that the problem appears to be in my ign. switch. They redid all of the wiring even though they could not repeat my situation by messing with the radio or its wires. When they wiggled my key in the ign. however it started powering the radio off/on. Does the ign. switch have a seperate power access. wire from it? I seem to have NO other issues, wouldn't the car stutter and stall as if the key was being turned off and on? As long as I'm on here I also have replaced one cruise brain and had another resoldered to no avail. I have no cruise. What is the next in line possible solution to the cruise? Opinions on just getting an aftermarket cruise added? Thanks in advance, Rick

Alan

Yes there is - just for the radio - terminal R.

Alan

dr bob

The 'accessory' circuit is different from the ignition and the rest of the engine smarts. Has to be so you can select accessories with position two of the ignition switch without running the engine. Notice that most accessories turn off briefly while the starter motor is engaged. This allows the engine to have full voltage for cranking the starter without all the drains from accessories. Meanwhile, it's been determined that a few critical systems like the ignition and EFI brains need power during the cranking operation.

Now for the good news-- The electrical portion of the ignition switch is avaialble separately from the lock part, so you can change it without needing a different key in the future. How cool is that! And because it's a fairly common failure/maintenance item, it's not priced like "the other one" of whatever ultra-rare part you just broke might be. On some cars, I've decided that whatever part I need to replace is surely the one that was first put on the assembly line belt for Hans and Fritz to start bolting things to when the car was under construction originally. The ignition switch isn't one of those parts! You can actually get to the ignition switch without removing the engine or the rear suspension. Hard to believe but yes it's true!

Alan

This is actually a seperate circuit with a distinct switch terminal that is seperate from all the other accessories. Most accessories are on the bus X, the radio only is on bus R.

In fact as long as you move the inductor (in the console - looks like a single sided transformer) in series with the radio supply (as it is from terminal R) - no reason why you shouldn't just switch the radio to an X-Bus supply and forget the R bus altogether.

I think the idea of a seperate R bus is to avoid interference from other items on the X-Bus - however 1/2 the supply is common anyway to the ignition switch and modern audio is usually rather less susceptible to supply induced noise. There are X bus supplies in the console... or you could switch a 30 supply with a relay triggered by X for a clean battery supply if noise was an issue. A good audio shop will know how to do this including to add a supply inductor and decoupling capacitors for reduced noise.

If I had no other symptoms I would not replace the ignition swicth for this.

Its a rather rare failure AFAIK.

Alan

dpower$

Why do I not see this thread on the rennlist 928 forum, but when I do a search for "ign. switch" it shows up? Thank you for the responses by the way. I simply had the head unit wired hot all of the time and I have no more problem....I also lost the alternator noise that was in the stereo. Rick