Alternator wire modification question
 

Hello- I have done the alternator wire mod from the How To Documents, works great with the John Deere HIR 9011 bulbs. I have an aftermarket stereo with Sirius Sat. Radio and amplifier in my 92 LS Pearl. My dilemma is, now that the weather is warm here in Boise, ID, when running the AC I get the whine associated with poor grounding through my stereo. Stereo installation was completed by a reputable shop in town. The amp is grounded to the chassis in the trunk, and the alternator mod was done exactly as shown in the write-up, with nice audio 4 gauge wire and great connectors. Everything is quite snug. Can I get away without the 2nd wire in the write-up, the AC compressor bolt to the negative on the battery? I'm thinking this may remove the whine. Thought I'd ask before possibly damaging the alternator. Or should I move the 3rd wire, the additional ground, to another place on the chassis? Or replace the factory ground with better gauge wire? Thanks for any advice. BIRD

P.S. I thoroughly enjoy the information provided on the website, it has enabled me to maintain and enhance a very nice automobile.

Maybe the alternator mod is causing the problem. Why don't you just try removing it completely and cleaning up the connections on the stock wiring?

It has been suggested, that if your charging system is working properly then you don't need the alternator mod - and if it isn't then you should fix it rather than trying to mod around the problem. Do a search for the many posts that Trevor has made on this subject.

I tried the mod a long time ago when it was first suggested and could find no measurable benefit, so I removed it.

I have that whine when running an mp3 player off the cigarette lighter in my Legacy. I didn't know that it was caused by poor grounding. I thought it was produced by a periodic fluctuation in the voltage produced by the alternator.

your alternator could be going bad (?)

Bird,

Please read the data in my locker regarding the alternator mod.

Grounding in respect of audio components can produce ground/earth loops. (Do a google on this.) If your original connections are not 100%, the extra ground wires could be producing/increasing this problem, but I have not investigated this possibility.

Slightly suspect rotary contact within an alternator, will produce noise on line. Electronic outlets will supply you with a capacitor to instal at the main outlet terminal on your alternator, as a means of noise suppression.

Trevor,
Do you know of any Internet-based sources for the capacitor? My local RadioShack is a bit "dim" on the topic.
Thanks.
-Bill

Find a small shop that does auto stereo and alarm installs.

Bill,
I got once got one from the largest producer of automotive crap - JCWhitney - and it worked great. This one was just spliced inline at the power line to the radio - not at the alternator. Worked great and is still in the wagon 15 years later. Probably too small to plumb in front of an amplifier, but worked fine on the radio.

The sort of animal described by Bill, comprises a coaxial capacitor and sometimes a choke and will certainly do the job. But it should be fitted in line, close to the audio/radio unit, which mean difficulties of access.

The capacitor I had in mind, is connected close to, and in parallel with the offending appliance, so that it is simple to fit. Cutting wiring is not required. This would be your first option and the most economical. If it does not do the job, go for an inline noise suppressor, as mentioned by Bill.

Thanks for the feedback. I removed the alternator mod and it is better, less of a whine through the radio, but I have not had the chance to do anything further. I intend to look into the capacitor. BIRD

I sincerely hope that others will take note of your experiences. :)