Installed a new battery today. But now my Radio and CD changer aren't working.

One little thing went wrong, and I am wondering if I did this to myself. Please don't ask me how this happened, but for approx 45 seconds, I connected the battery cables to the wrong battery terminals.

I am wondering if I somehow blew my audio components by doing this. I checked the fuse that goes to the radio, and it appears okay. It's not a radio security code issue, as far as I can tell. Isn't the radio supposed to ask for the code after the power's been cut off? Well my radio just sits there dead. The little red flashing light isn't even blinking. I think I killed it, unless there's some other fuse or relay that I should be checking.

Any helpful thoughts are most welcome.

Dear Fab Phil,

Good a.m. and may this find you well. Don't panic, at least not yet. On some 940 e radios, there's a 5-Amp, blade-type fuse in the back of the radio box. If you radio has such a fuse, inspect it. I suspect you'll find it burned through.

You'll need to remove the radio, to access this fuse. See the FAQ's under SITE FEATURES, for guidance on accessing/removing the radio. If you have any questions, post again. I'll try to reply in a timely way. Many others on the Board have also pulled/replaced the radio, so you'll not be "stranded" for very long, if at all.

In case replacing that fuse doesn't solve the problem, the Board's electrical experts might find useful, answers to the following questions:

(a) Was the ignition switch off, or on, for the 45 seconds, that the battery was mis-connected?
(b) Did you try to start the car, while the battery was misconnected?
(c) Are any other items not working (e.g., power seat[s], lights, heater blower)?
(d) Have you replaced the fuse, that protects the radio circuit?
(e) Have you started the car, and if so, does it run "normally"?
(f) If not, are there any OBD Codes?

Hope this helps.

Yours faithfully,

spook

Greetings! I was delighted to see your reply, Spook. First because of it's hopeful tone, and secondly, because it's from you. You are such a gentleman on this board, helping freely those less experienced than yourself.

I pulled the radio, a model SC-811, and there doesn't seem to be any sort of fuse on/in the unit that I could find. Ahhh... such a simple solution would've been sweet. (By the way, kudos to the Volvo engineers for the simple manner with which these units can be removed from the dash. Nearly all of the other cars I've owned required tools and harch language to accomplish the same thing!)

But now to your questions:

The During the short time the battery was mis-installed, the key was never turned in the ignition switch. Never touched it.

The rest of the powered components in the car appear to be working normally, which is a relief. Seats, windows, moon roof, heater, all good.

I replaced the fuse with one I know to be good, and there still was now life in the radio when I attempted to turn it on.

I do not have a voltage tester or a code reader, but all appears normal. The car starts and drives just wonderfully. The only thing amiss is the radio. When I turn the ON knob, the radio does nothing, and the antenna mast does nothing. Further, when I press the eject button on the CD changer it does not react. So either it isn't getting power, or it's fried too.

I can certainly pich up a usedradio unit, and swap it in, and see if it works. It appears that either the radio is fried, or the Volvo engineers built in some sort of pre-fuse to protect the audio components from troublemakers like me.

Not sure if this is terribly helpful, but that's my descriptino of the state of things with this problem. If only all my other worries were this small!

Thanks in advance for all your help!

Warmest regards,

FabPhil

Regarding the codes… you should have OBD-1. OBD-II (the one requiring a reader) didn’t start until ’96.

You can flash out the codes by following the instructions at this link:

Engine and OBD Diagnostic Codes

I don’t think you’ll get any codes on this, but it would be good to learn how to do it.

What you should do is to pick up a voltage tester and test the green/red wire going into the radio (constant power).

Just check radio shack or even the electrical section of your local hardware store (Lowe’s, Home Depot, Menards, etc.)

A couple of examples:

Automotive multi-tester

Volage tester

Check the batt+ wire (green/red, constant power). If it has power then it’s the radio. If it doesn’t, then I don’t know what to do next.

Assuming you have an amp, here’s what the rest of the wires should be:

Radio

LF+ Dash speaker Brown/White
RF+ Dash speaker Grey/Red
LF- Dash speaker Brown
RF- Dash speaker Grey
Dimmer-Yellow White
Rho + white
Rho- Blue
Batt+ Green/Red (constant power)
Ground Black
Power Antenna - Orange (this is the one that you want to use for the power antenna from your new tape deck)
Power Antenna Green Grey

If it is the radio and you can’t figure out how to fix it, you do have a 10+ year old tape deck. Consider putting in an aftermarket CD head unit, maybe one with MP3/WMA capability.

Dear Phil,

Good p.m. and glad to learn that your car's well. There likely is an internal fuse, one mounted inside the radio case. I don't know how to access it. I'd bet one of the Board's radio gurus will know exactly.

Best of luck with this.

Yours faithfully,

spook