Dashboard Switch Illumination Repair

[ejboyd5]

With the exception of the headlight switch, most Porsche pull/push dashboard switches, i.e., fog light, driving light, auxiliary heater, rear window defogger, etc., were designed to be internally illuminated when activated. Unfortunately, over their lives some of these switches have lost this ability with the causes ranging from a simple burned out lamp or incorrect wiring to a missing lamp socket in the switch itself. Thankfully, help is at hand.

If the problem is a faulty lamp, Stoddard (and probably other vendors) offers part # 900-631-102-90, Dash Lamp Bulb, 12V 2W BA7S for $1.49. If the socket is missing, part # 644-741-901-01, Single Spade Bulb Holder, $7.20, is what is needed.

As mentioned in other posts, the dashboard pull/push switches are elementary in design with their terminals “1,” “2” and “3” being internally interconnected and terminal “K” being internally connected to a brass plate that makes contact with the Single Spade Bulb Holder. In order for the lamp to illuminate, it is necessary to fabricate a jumper wire to run between any one of the numbered terminals and the spade connection on the bulb holder. The remaining numbered terminals are used for positive input and output to and from the switch while terminal “K” is connected to ground. Since switches could not care less which way the electrons are streaming, if you are using such a switch to control the negative or ground side of a circuit through terminals “1,” “2” and “3,” terminal “K” must be connected to the positive side of that circuit for the lamp to illuminate.

[merbesfield]

Nice work. You should consider using heat shrink over your connections to finish it off and give some protection.

[Bill Simmeth]

Very well written overview, thanks. I didn't know that the sockets were still available. -- good to know.