Erratic Radio

[umbrobryan]

Hello to all and thanks in advance. My dad and I have a 93 ATX that has a JBL audio system in it. He has primarily used it since it gets better MPG than the 99 F-150. Since its gotten warm hes been riding his Harley and Ive been driving it doing odds and ends such as oil change, subframe bushings...and so on. One of his complaints he wants me to addresse is a radio concern that im kinda scrathing my head at.

The problem is the radio volume cuts in and out. There is no rhyme or reason to it either. The head unit will always stay turned on. You can change channels and watch the volume indicator go up and down but there is no volume. The tap test on the headunit and amp reveil nothing. I wanted to check the remote wire to the amp. I backprobed the amp and found 5.5-5.0 volt on the DVOM. This is where I began scratching my head. I flipped the DVOM to ohm and found it was also shorted to ground at the same time.

I thought that maybe the harness was shorted somewhere between the head unit and the amp so I cut the remote about 2 inches away from the headunit and retested. I found the same reading 5.5-5.0 v and short to ground at the same time.

Now I know that SHOs are special but ive never seen a remote in an audio system that was 5.5-5.0v with a short to ground at the same time. Its always been battery volts. Has anyone else seen this before??? I believe I have a bad headunit. The only reason I can think this would make the amp act funny is b/c this is possibly border line voltage to tun on the amp. Any thoughts???

Thank you much, Bryan

 

[the4biddendonut]

The remote turn on wire is supposed to be 5 volts. That's not your problem.

It sounds like you may have a short in one of the speakers or the speaker wires. When a that shorts to ground, usually the head units go into protection mode.

 

[umbrobryan]

This sounds feasible. Do you think if I uplugged one of the rear speakers and stuck a paperclip in the terminals to simulate a shorted spearker then the radio will do its thing???

I think ill try it. I mean, whats the worst that can happen? Right I kinda got a feeling that that theres nothing wrong with the speakers though. They still sound great 214k later. Its missing the sub though. If this does indeed simulate the problem I will go ahead and replace them anyway. Right now I have MTX speakers in my 98 and they sound fantastic with a 12" Power acoustik sub and a pioneer head unit.

Another question in my way of thinking would be wondering that if one channel would short, only that channel would be dead. However I didnt make these toys, I just play with them.

Thanks for letting me know that the remote is only 5 volts. To be honest, ive never hooked a DVOM upto a remote, not even aftermarket. Never thought too. It always just been hook that wire to the remote terminal, and they have all worked. Ill have to check my other car now.

Ill give an update after I get it back in the shop. Thank you much, Bryan

 

[Pro*banshee]

Yeah that's the failure mode for most OEM radios when encountering excessive current draw.

General motors ACDelcos usually switch off while Ford ACDelcos just lose or gain volume. After market Cd players pop fuses