Name this wire

[avanwinkle]

 Owned the 1970  since 2012.  Great weekend driver. Just starting to get under the hood.  And have a lot of questions.  Here is a frayed wire that goes from area around radiator overflow to the interior of the car.  Let me know if you can identify the wire and also what should be done with wires showing and insulation missing.

Also, I have a Haynes Repair Manual.  Is there a better book for maintenance, repair, and overhaul for this vehicle.

Thank you.

AVW

[hkollan]

Hi,

Looks like the red wire for the radio.  A bakelit fusebox and a bracket is needed to make this correct.

Hans

[georgem]

I`d name it as - dangerous - with what looks like decayed insulation and exposed core. It started out as black and appears to be joined. If its live, I`d replace it asap.

[ja17]

Looks like an  add-on for some type of accessory. The hole and rubber grommet, it passes through, is not factory either.

[Tyler S]

That is the same place the wire passed through the firewall for my dealer installed Blaupunkt. It was a perfect place for a water leak into the dash. I have since relocated it to the other rubber plug/grommet on the firewall just aft of the coolant reservoir.

[hkollan]

Hi,

This red wire for the radio is AFAIK present in all the wiring harnesses, at least on the 280's, possibly also on the 230 and 250's.
If the car came with a factory radio(Becker) option it was used in conjunction with the bracket and fusebox on the right inner fender.
 In other cases it was taped down and hidden in the harness, but still present to be retrieved when needed.

Hans

[cfm65@me.com]

Hi Guys,
My 250SL has the same hole in exactly the same spot as Alex car.

[Tyler S]

My 250sl has the hole as well. It is a drain hole for when the body was dipped in anticorrosive bath. That area is like a bowl and a hole was needed to drain off the excess. A rubber plug was then placed there to seal the hole. Dealers often used this hole to run the power feed for a radio install since it is easily accessable under the dash.

[Jonny B]

Ya made me look. My 250 SL (early) has the hole and plug. The 280 SL (12730) also has the hole and plug. The 280 SL has a radio, and the wire is not routed as the picture. There is a red with green strip wire coming out of the wiring harness, just under the voltage regulator that goes to the small brown fuse box in the right inner fender. The wire coming out the other side of the small fuse box runs to a grommet on the fire wall below the coolant tank.

[Tyler S]

The wire coming out the other side of the small fuse box runs to a grommet on the fire wall below the coolant tank.

Yep, Thats where I re-routed mine to.