Dash lighting fuse installation

[RWebb]

Guys:
I'm resurrecting this ancient & excellent thread to see if anyone knows what these terminals look like on the early cars (say, a 1973.5)?

Mine has 2 different places that appear to have blue/black wires going in - one on the outer ring of terminal and one on the inner ring (yes, the terminals on my car are arranged in two concentric rings).

I don't see any #'s near the switch terminals, but then I have not gotten the magnifying glass out yet either - am hoping to avoid that...

[jittsl]

I don't know if this helps but in my 1970 there was 2 black/blue wires both connected to terminal 58a. One is for dash lights and one is for ashtray. Both deserve to be fused.

[RWebb]

thx - I may need to get out the ohm meter

[HarryD]

Randy,

Looking at the electrical diagram: http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_1973_CIS_Part1.jpg

Part number 32 is the headlamp switch and instrument light dimmer. There are 3 wires coming off of the rheostat "terminal 58a": one red/black and two blue black. you will need to interecept all three of these and put the fuse between terminal 58a and these three wires.

[RWebb]

thx, unfortunately I can't find that exact configuration on mine (!)

[GeorgeK]

Randy,
Pull the black/blue wires off one connection and see if the dash lights go out. That would be the bundle to fuse. If both bundles light different parts of the dash, two fuses.

[HarryD]

On my car, the red/black wire goes to illuminate the Hazard Flasher after going through a resistor to dim the lamp. Per the drawing, one of blue/black wires goes tothe instrument lights and the other is to illuminate the ash tray and heater control light on the tunnel.

[911pcars]

Originally Posted by HarryD

On my car, the red/black wire goes to illuminate the Hazard Flasher after going through a resistor to dim the lamp. Per the drawing, one of blue/black wires goes tothe instrument lights and the other is to illuminate the ash tray and heater control light on the tunnel.

The resistor being the light switch (rheostat or potentiometer). At the full bright switch setting, there should be full source voltage for the bulb circuit. If there's any voltage difference, try temporarily bypassing the switch and see if the panel bulbs become a tad brighter.

Sherwood

[tmadden2]

I recently completed this modification as well. I tried taking the seat out, but still had a hard time figuring out what I was looking at. Removing the left A/C vent gave me a much better view of what was going on and being able to get one hand under under the dash let me work from both sides of the light switch when it came time to reconnect the fuse terminal to the switch.

[armand80sc]

I'm resurrecting this this old but excellent thread with a question:

What size male spade and female terminals are required to be joined to the fuse holder??

[wrxnofx]

Originally Posted by armand80sc

I'm resurrecting this this old but excellent thread with a question:

What size male spade and female terminals are required to be joined to the fuse holder??

I think it's the 14-16 gauge size. I believe they are the same as pretty much every other terminal in the electrical on this car.

[sugarwood]

Yes, they are 14-16 gauge.
More basic info here
Is it OK to fuse all 3 wires going into 58a for dash light fuse at headlight switch?

[armand80sc]

Perfect! Thank you

[Mygas]

Gentlemen,good evening. (If there are any ladies reading this,forgive me. You're honorary blokes!)
This thread,and another,"fusing the dashboard lights. How to," make scary reading. Thank you all for the info and recommendations. Just thought I'd add my 2 pennies worth.
The car is an '88 939 Turbo Targa and RHD.
To fuse the dash lights I found it easiest to remove the light switch from the dashboard. Pop the cover and remove the retaining nut,then undo the retaining ring. More than enough play in the wiring to bring the switch into view below the dash.
I found that the interior courtesy lights in the cab,the light in the bonnet and the engine bay,the clock and the radio,and the glove box light are all on the same circuit protected by a 5 amp fuse in the bonnet fuse box. It's no 4 on mine,and being Porsche,it's numbered from the right as you look at it from above! Still needs the conduit for the glove box wiring but at least it's a relatively reasonably rated fuse.
Sadly,I was too late for the air con condenser blower. Dead as a dodo,with a blackened winding. Still,at least the wiring was intact! There are a few replacement options.
1)A Porsche fan. Complete with housing etc. Comes in at about £255,or $420.
2)APelican replacement motor.$195,or $85 for something of which there is no picture.
3)an uprated blower,fan and housing from RetroAir.com which comes in at $185.
I went for this last,so we shall see.
The footwell blowers were already fused with 10amp fuses,1 of which had blown with a seized fan. Freed this off and now works perfectly.

So far so good! Thank you all so much for your help

[garyhahs]

Hi---can you tell me where the other wire goes once the wire is on 58A. Thank you.
Gary

[356911930]

The "other wire" plugs into the connector you removed from the 58a terminal.

Rahl

[Reuben911]

Thanks guys

It was a quick fix and took me 10 mins to install in a RHD, thanks for the help. Took me longer to find a 3 amp fuse

[jlex]

Just got around to fusing the interior light circuit a few days ago. Thanks to Charlesbahn's instruction to simply remove the light switch from the dash first, it was an easy job. No gymnastics required. My '88 did not have the protective plate at the bottom.
As additional information, I'd like to add that in order to remove the light switch knob, you must first pull it out which exposes a hole in the stem of the switch. To keep the switch from rotating while unscrewing the knob, you need to insert something (like a drill bit) thru those holes first. Simply turning the knob to try to unscrew it may damage the switch. Easy job; just remember to disconnect the battery first.

[Quasimoto]

Originally Posted by jlex

As additional information, I'd like to add that in order to remove the light switch knob, you must first pull it out which exposes a hole in the stem of the switch. To keep the switch from rotating while unscrewing the knob, you need to insert something (like a drill bit) thru those holes first. Simply turning the knob to try to unscrew it may damage the switch. Easy job; just remember to disconnect the battery first.

Just added this fuse while my seat was out. My car has the plate in the corner, so taking the switch out was necessary. Thanks for the tip about the hole in the switch shaft!

[jlex]

You're welcome. I came pretty close to breaking my switch before I figured that one out.