choke control switch

[qz16]

preface:

I am working on the restoration of a 73 240z.   A mentor of mine used to say “The enemy of good is better”.  I adopted this saying but often times I unfortunately ignore it.

Our car “the bucket” has what I believe is its original center console.  It has a single slot on the driver’s side for the choke control.  At some time in the past the original choke control arm and bracket were replaced with a generic pull out handle and cable mounted where the cigarette lighter would normally be located.  It worked well enough with the previous owner’s conversion to a Holey 4 barrel.  I returned the car to a dual SU setup.  The choke reminder lamp was also replaced with a blank piece of plastic.  I could have used the generic control for the SU setup, but “the enemy of good is better”.

 

I looked at the Console and I looked at the empty slot for the choke control and once again I ignored my training – “the enemy of good is better”.  I located a choke control arm, original cable, and a choke indicator lamp.  I purchased a bracket to mount them on the transmission tunnel so that the 40+ year old plastic console would not be stressed by the mechanical action of the choke control.  I wired in the lamp taking a silly shortcut using power from the rear defroster switch.  I believe the switch plastic failed and that set up a nasty sequence of events.  Ultimately a short melted the plastic choke control switch before it could be protected by blowing a fuse.  The hatch defrost circuit has a 20 amp fuse.  It blew but too late to protect the mini switch.  I know better but I made a number of silly mistakes that I am not proud of but my errors led me to a fix that I thought might help you. 

 

 

 

choke control switch alternative:

if your choke control switch is not working and you need to replace it this might help. 

Above is the original choke control switch.  Normally it has 2 leads, but one was weak and it broke, which probably helped to create the short that melted it.  It mounts to the control arm bracket with two screws thru the holes on either side of the switch.

Above is the control arm bracket.  The pen is pointing to the hole where the switch button protrudes when mounted.  The threaded holes on either side are to mount the switch.  I could not locate an original plastic switch.

 I decided to use a limit switch and bought the following on Amazon.

MXRS SPDT 1NO 1NC 5.5cm Hinge Lever Momentary Push Button Micro Limit Switch AC 5A 125V 250V 3 Pins 12 Pcs.  Hard to believe but 12 switches cost less than $7.00. 

Above is the original switch on the left and the switch that I bought on the right.  The nice thing about this switch is that there are three pins which allow you to alter its definition.  Depending on which pins are used the switch can be either normally open or normally closed.  The issue for me was a mechanical one – mounting the switch.  Naturally it does not mate to the control arm bracket in the same fashion as the original.  There are two holes that go thru the body of the new switch.  So the mounting orientation is off by 90 degrees and the red button is not long enough to protrude through the bracket like the original switch.  I wanted to make as few changes as possible to the control arm bracket.  Only one additional hole was necessary.  I also cut part of the bracket to provide more clearance for the pin that returns to the indicator lamp .  

Above is the control arm bracket with the new switch mounted to it.  The pen points to the lever (shortened) of the limit switch.  If you look closely you see the red button that it contacts when the control arm (black handle) contacts the switch lever.  The bracket is upside down in the picture.  The control arm is in the activated position, equivalent to applying the choke for starting, pulling the cables, the indicator lamp would be lit. 

In order to mount the new switch I had to enlarge the mounting holes in the switch body.  I enlarged them to accommodate #4 metric screws.  There is at least enough room for this, just go slowly.  The new switch is actually mounted to the horizontal plate that I bought separately to eliminate the need to attach the control arm bracket to the bottom of the center console.  There are a lot of benefits to mounting it to the transmission tunnel.  It is a real pain to remove/install the center console with the control arm mounted to it.  The 40+ year old plastic is brittle and a common complaint Is that the control arm cable binds and the stress breaks the plastic center console.

 

Above is a picture of the choke control in the inactive position, cables released.  You can see the red button and the switch lever.  They are depressed so continuity is broken and the indicator lamp is off. 

 

in the image above is the control arm and bracket.  It is upright, the front of the car is in the direction of the keyboard.  The arm is forward, the choke is off, the indicator lamp is extinguished.

above is the control arm and bracket. Just in front of the original switch mount is where I removed a small part of the bracket for extra clearance for the pin the extends out of the new switch back.

If you have any questions feel free to ask away.

 

Edited August 25, 2020 by qz16

[cgsheen1]

Good job Q!