I had the XM Pioneer modulator put in my C5. worked great in the day time. After the lights come on nothing but static. Had "Good Guys" look at it and tried to fix it. No luck They called XM and Chevy and were told the radio in the vette is not compatable to the modulator. So i had the unit removed and the LOSERS at GOOD GUYS refused to refund my installation fee. I guess it was my fault told sold me something that won't work in my car. Just a warning!!!

 

Sorry to hear about your problem. This is the first time that I have heard about this issue and it makes me re-consider my purchase of an XM radio for the Vette. Did you get a chance to talk to the Store or Regional Manager at Good Guys (I use the name loosely)? I am sure they would be willing to refund your $ when you mention the bad press and feelings this has caused...Good luck!

 

That's the nice thing about scrapping the Blows system. Anything aftermarket is better than stock. Plus the Modulators suck

 

I have contacted Good Guys customer relations twice with promises of a call back as of one week no resolution to my problem.

 

When you get any other work done from a service related person, do you ever get a refund on the labor?

 

yes, i'm in the service industry and if we ever sold someone something that was defective or was not compatible with their equipment we would always refund the service. afterall they came to us because we are supposed to know what they need. if you don't expect that kind of service i am surprised.

 

Not to make this personal, but shopping as a uninformed consumer isn't very bright. You do research before buying a house? You do research before buying a car? Most people research other decisions. Everybody knows the Blows system sucks and nothing is compatable with it.

Instead of bitiching with them about a refund, tell them you aren't happy till it works and they had better find away for it to work. Or just junk the pioneer modulator and buy a new stereo set up and be even happier. :jester

 

"After the lights come on nothing but static."

Try to explain this again. What do your car's lights have to do with FM radio reception.

P.S.

Try not to listen to C4 owners describe a C5 Bose system. The two system have nothing in common technically.

 

The tech from Chev told the "Good Guys" installer it has something to do with the computer in the radio and how the radio is grounded. He showed me the back of the radio and everytime we turned on the lights the static was heard. After the lights went off no problem. Sorry to sound like an idiot but that is why I go to someone supposely trained too purchase an item. If I had time to research everything then I wouldn't need any sales personal input. But on the other hand if I spent all my time researching something I wanted to buy I wouldn't have time to make the money to buy the products they sell.

 

What frequency was the XM modulator tuned to?

 

As 99HT is about to allude too... Your XM FM modulator should have had NO problem with your lights, or anything else for that matter. You simply had a faulty XM receiver. Go back and get a new one. Or, better yet, get a stinkin refund, and go somewhere else!

 

We actually tried changing the frequency twice. It didn't help. We were at 88.7 or somewhere around there. As far as a bad modulator, we did switch it out once, we also switched the antena. I don't know why there was a problem and what the lights had to do with it, I just know it didn't work and as soon as the lights went off it cleared up. The tech was totally baffled as was the XM tech. It was someone from Chevy that told him it wasn't compatable. P.S. I got my refund on the install.

 

There is probably something wrong with the installation. The C5 has had FM modulators installed for many accessories with no problems. The CD changer that Delco designed for quick dealer installation has an FM modulator. I suspect that there was a ground loop created between the XM receiver and it's modulator. If the installation was done different, IE power and ground wired differently, then you would probably have no problem.

I believe that the dash light dimming system in the C5 uses pulse width modulation. Pulse width modulation is a method of digitally varying the power delivered to a load with only a switch. The big advantage to this method is than very little heat is generated in a low resistance switch which is only ON or OFF. This is versus the normal method of using a rheostat to dim lights. It is also much cheaper. The average power delivered to the load is proportional to the duty cycle, ON time versus OFF time. 0% duty is no pulses and 100% is on constantly or DC. 50% duty is ON/OFF equally.

If somehow your XM modulator and receiver was grounded in a way that the "pulses" of current going to the bulbs had a sneek path through the XM system, then you might "hear" these pulses in the audio if the switching speed was audible.

This is only a guess since I am not there to measure anything.

 

I would have to agree with 99HT, PWM is a very common way to control a particular load. I have performed Power Quality surveys in many electrical distribution systems (large facilities), and you wouldn't believe the number of systems using PWM for load control and the ill-effects on communications equipment. And even if the PWM system is operating at low frequencies, there are harmonics and transient impulses created from a square-wave. Without proper grounding and filtering, these systems are very susceptible to noise injection. I would be interested in seeing an oscilloscope view of several points in the system to see what is happening. Usually the guys that are good at figuring out these types of problems have the right equipment to "sniff-out" the problem.

Good luck...

 

:crazy: Hmmm, I think it's the XM radio satellite itself. You said you had the problem when your lights are on, meaning it's dark, so the satellite's in the dark, too, so its solar panels aren't getting any sunlight, no power, no signal...
Just kidding! My mother used to tell me I have a fertile mind. And we all know what fertilizer is made from... :)

But seriously, where does the average Joe find a local guy with the tools and the talent to help him diagnose this problem? Stereo installation shops clearly aren't helping...Any clear resolution, yet?