1999 S70 Radio SC-813 LED's flicker and are out

1999S70B · Post by **1999S70B** » 04 Nov 2013, 22:38

I am in the process of adding an antenna down switch to my SC-813. I received the Volvo wiring harness today and installed it, but am still waiting for the switch to arrive. I noticed when the engine revved between 2700 - 3000 rpms, only the radio LEDs would dim and flicker. When the revs dropped, the LEDs returned to normal brightness. The weird part was no other light on the dashboard flickered. Then when the engine got to about 3000 rpms, the LEDs went out for the last time.

Does this sound like a vibration issue with the wires themselves, or did the extra wiring harness without a switch have a factor?

Post by **Ozark Lee** » 05 Nov 2013, 06:36

Which LED's are you talking about? The only LED on my SC-813s are the security LED.

...Lee

Post by **rspi** » 05 Nov 2013, 14:06

I added a switch to our S70 but did NOT add any special order harness or anything. I took a S70 fog light switch and replaced the fog picture with an antenna switch picture.

http://m.volvoforums.com/forum/showthread.php?t=30891

As for light bulbs...

Post by **rspi** » 05 Nov 2013, 14:07

1999S70B · Post by **1999S70B** » 07 Nov 2013, 16:26

After further investigation I have found:
The backlights do work when only connected to the original wire harness.
The backlights do NOT work when the adapter harness is installed.

I tried wiggling the wires around while the unit was on to see if there was a loose connection somewhere that would cause the backlights to turn on - that didn't work.
I noticed the backlight to the antenna switch itself was not working. Does anyone know if the switch light and the radio backlights are wired in series?

On another note, I had to install the switch to the left of the steering wheel. I was wondering for those who have added this switch, did you route the wires above or below the steering column?

Post by **Ozark Lee** » 08 Nov 2013, 20:10

The instrument lighting and the radio lighting is all run in parallel off of the dimmer. The pink wire on pin 10 of the A connector to the radio is the lighting circuit.

...Lee

1999S70B · Post by **1999S70B** » 15 Nov 2013, 21:58

Ozark Lee wrote:The instrument lighting and the radio lighting is all run in parallel off of the dimmer. The pink wire on pin 10 of the A connector to the radio is the lighting circuit.

...Lee

That is exactly where the problem was. The spade terminal in the connector was loose, so when I plugged the connector into the radio, it pushed the terminal out the back of the adapter leading to a faulty connection.
Now with that connection solid, I have backlights and the radio. Perfect!

Thank you very much for your help.

Post by **rspi** » 16 Nov 2013, 08:23

Wow, sounds like my $4 switch mod would have been a much better option.