PDA

View Full Version : strange issue, radio only works when fan blower is set to4


spreyjay
03-01-2017, 10:47 AM
.well this has me stumped, I can only use my stock oe radio with the fan blower set to its highest speed. Dropping it to any other speed makes the radio cut out. It does not need the code re adding when I go back up to full speed on the blower, it just Suddenly comes to life.

Blower itself works fine on all settings.

Any ideas?

Aqua Puttana
03-01-2017, 04:07 PM
.well this has me stumped, I can only use my stock oe radio with the fan blower set to its highest speed. Dropping it to any other speed makes the radio cut out. It does not need the code re adding when I go back up to full speed on the blower, it just Suddenly comes to life.

Blower itself works fine on all settings.

Any ideas?
Could be some sort of backfeed loop. I would first check all of the fuses under the steering column. Don't just trust the fuse map because that information can be incomplete.

If all of those fuses are ok, then check the fuses under the the driver seat. Fuses there are less likely to be the culprit, but you never know with Mercedes.

Use a flashlight. An open link can sometimes be difficult to see.

vic

autostaretx
03-01-2017, 06:37 PM
On fuse block 1 (under the steering wheel), check out both Fuse 8 and Fuse 15.
Fuse 8 is the "permanent" power to the radio, Fuse 15 is the "key turned on" power.

((i'm still looking at the schematics for a blower/radio cross-feed))(4 splices (S250, S252, S255, S210) are my prime suspects)

(a few moments passed...) Does your cigar lighter socket follow the same pattern?
(not the 12v power outlet on the panel, but the socket that's hidden in the front ashtray)
That socket also is tied to splice S252 (hence fuse 8).
.. but since your radio is not losing its Code, i doubt that that circuit is the one at fault.

Chunks of the Aux Heater system do share the same Ground point (G203) as the radio.

I suppose i could always cop out and suggest that it's damage inside Fuse Block 1 that's causing cross-connects.

--dick