When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
'94 SC Stereo / factory Cell Phone (sort of) Problem
Hi all,
Been a member of the "club" since 2012, got all the info I ever needed via existing threads (thank you very much) ... until now.
Made the decision after a long, slow decay of the factory stereo (down to an intermittent passenger side door speaker and/or tweeter) to revive the system. A darn fine system I might add IMO.
The car is not mine (my girl's), so I hadn't realized how bad it had gotten. The one remaining speaker would go from normal volume level, suddenly VERY loud and then back to normal. Told her to stop using it altogether for fear of frying the tweeter (hoping I could salvage them - which in fact I did). I also noticed that all audio controls on the radio were non-fuctional now ... FADER did not fade ... BAL was unresponsive etc and the Volume control had dead spots between zero & 10 o'clock.
After much research I purchased 4 replacement Dayton Audio raw drivers and a pair of Peerless dual ring radiator tweeters (just in case).
Everything came apart much easier than expected. Credit due to more than one well-documented online thread and the invaluable Factory Service Manual (go get one if you don't have it)
Rear deck speaker foam rings were all but gone, one showed totally dead on the multimeter, one very high resistance. One door speaker stone dead, other one showed 4 Ω but made no sound.
Long story short - all speakers hooked up - original Nakamichi tweeters alive and well. Oh yeah - subwoofer is fine as also. Head unit audio controls fully fuctional! (Volume control included) Awesome right? Wrong. Turn car off, come back 20 minutes later ... front passenger speaker only ... AGAIN. What the?
Do more research .... educate myself about the factory cell phone transciever / speaker relay. this MUST be the problem right? Cellphone operation shunts the incoming call to the passenger side door speaker via the speaker relay (which are known to go to *****). Go looking for this unit and what do I find?
Gratuitous *** shot
Cellphone transciever / speaker relay connectors
The cellphone box is long gone, speaker relay bypassed (note the connectors plugged in to each other) and yet - the stereo is behaving as though it were still there (sort of).
I separated the connectors, cleaned the contacts (they looked clean already), it behaves the same. Anyone else run into this?
Ahh ... this could be useful. Was considering bypassing large lengths of this passenger door speaker wire (the whole loop through -what used to be the phone transciever / relay). traced a lot of the wire but this is a whole other level. Wondering if a short to ground could be the problem. Anyway ...
08-12-18, 11:50 AM
'94 SC Stereo / factory Cell Phone (sort of) Problem
and then back to normal. Told her to stop using it altogether for fear of frying the tweeter (hoping I could salvage them - which in fact I did 
). I also noticed that all audio controls on the radio were non-fuctional now ... FADER did not fade ... BAL was unresponsive etc and the Volume control had dead spots between zero & 10 o'clock.
