'68 Wiper Switch Ground

[Joel K.]

While checking the forums for info to help get a '68 wiper system working, I noted several references to broken bezels affecting the ground for the switch. Being an electrical dunce, I'm confused; how is the switch grounded to the bezel?

[Terry B.]

Re: '68 Wiper Switch Ground

Good question Joel. I'll make a general comment that will get the question back at the top of the list.

The bezel is very thin as you move up the sides on '68's. Many break on each side toward the wiper switch causing the ground to be lost. I would think that the gauge cluster is grounded some where on the bezel. I do know that you can go to a lot of expense thinking something is wrong with your wiper motor or your vacuum system when all it is is the switch is not grounded because your bezel is broken and not grounding the wiper switch. That was an expensive lesson for me.

[Joel K.]

Re: '68 Wiper Switch Ground

Thanks, Terry, for the reply. I checked the bezel and it's not broken anywhere. Going back to my original question, how is the switch grounded at the bezel? The black (ground?) wire that comes off the switch feeds back into the harness. Should I be looking for an another grounding point on the bezel somewhere?

[Bryan M.]

Re: '68 Wiper Switch Ground

Joel,
If I'm interpreting the 68 wiring schematic correctly, the switch is grounded via attachment to the wiper bezel.

On my 68, the wiper bezel is grounded via attachment to the instrument bezel. There is a ground wire originating from a cluster of ground wires in the harness that attaches to the back of housing that holds the gauges.

[Joel K.]

Re: '68 Wiper Switch Ground

Joel,
If I'm interpreting the 68 wiring schematic correctly, the switch is grounded via attachment to the wiper bezel.

On my 68, the wiper bezel is grounded via attachment to the instrument bezel. There is a ground wire originating from a cluster of ground wires in the harness that attaches to the back of housing that holds the gauges.

Thanks again, Bryan, for filling in some of the blanks. So after reading your post, I (reluctantly) pulled the gauge cluster from the '68 -- but found no ground wire attached to the back of the gauge housing anywhere. Can you tell me where on the back of the gauge housing a ground wire is supposed to go? Not finding any loose wires that might be it, either. The only thing that appears to be a ground wire is a double wire with a female connector that I believe goes to a lug on the shifter plate by the ash tray. On the Doc Rebuild wiring guide it's referred to as a "console ground".
Still able to work the wiper motor w/direct application of 12 volts, but once it's in the car and everything's connected, nothing happens when the wiper switch is turned on, except that the wiper override light goes on when the battery's connected. This thing is getting very close to driving me to drink!!!

[Joel A.]

Re: '68 Wiper Switch Ground

The wiper switch is screwed to the bezel. The bezel is screwed to the metal framework on the dash. This provides the ground for the switch. The wiper switch housing/casing itself must be grounded for the wipers to work. The wipers have 12v all the time(key on), and it is the switch that provides the ground. Lots of folks will run an extra ground wire from the metal bracing to one of the screws that hold the switch to the bezel, to eliminate any issues with the bezel not grounding. Something as simple as using the wrong screws to attach the bezel to the dash can cause a loss of ground at the wiper switch.
hth

[Bryan M.]

Re: '68 Wiper Switch Ground

Joel,
Does your small gauge lighting work?

[Joel K.]

Re: '68 Wiper Switch Ground

The wiper switch is screwed to the bezel. The bezel is screwed to the metal framework on the dash. This provides the ground for the switch. The wiper switch housing/casing itself must be grounded for the wipers to work. The wipers have 12v all the time(key on), and it is the switch that provides the ground. Lots of folks will run an extra ground wire from the metal bracing to one of the screws that hold the switch to the bezel, to eliminate any issues with the bezel not grounding. Something as simple as using the wrong screws to attach the bezel to the dash can cause a loss of ground at the wiper switch.
hth

Thanks, Joel, for continuing to make sense of the wiper switch ground arrangement! I will try running a ground wire from a switch mounting screw to see if that solves the problem!

[Joel K.]

Re: '68 Wiper Switch Ground

Joel,
Does your small gauge lighting work?

I'll have to recheck that; can't say for sure.

[Bryan M.]

Re: '68 Wiper Switch Ground

I'll have to recheck that; can't say for sure.

The instrument bezel will have to be grounded for the small gauge bulbs to work. If I remember correctly, my bezel was grounded with a ground wire attached to one of the small gauge housing screws.

[Joel K.]

Re: '68 Wiper Switch Ground

Once again, thanks for the inputs, Bryan and Joel.
OK, I checked the gauge lights and they weren't on, so I ran a ground wire from one of the wiper switch mounting screws to one of the braces behind the dash. Lo and behold, the gauge lights came on and when I turned the wiper switch on to Low, the wiper door hinge mechanism actually opened!!!! BUT -- still no wipers! and when I manually moved the wiper door hinge back to the closed position, they moved right back to open again. Wondering if this points to a malfunctioning vacuum solenoid?

[Bryan M.]

Re: '68 Wiper Switch Ground

Did you have the wiper service switch turned to the right and is the switch properly grounded?

[Joel K.]

Re: '68 Wiper Switch Ground

Did you have the wiper service switch turned to the right and is the switch properly grounded?

I had a replacement two-prong override switch in, and had a ground wire in place. The switch was turned to the right. Interestingly, when I pulled that switch and put the original single-prong switch back in, and turned it to the right, the wiper override light finally went out. Didn't have a separate ground in place for that switch. The wiper door mechanism opened when I turned on the wiper switch...but still no wipers.

[Jack H.]

Re: '68 Wiper Switch Ground

In general, when the wiper door opens via vacuum, it pushes against a microswitch on the firewall. That allows power to flow to the wiper motor. Also, the over-ride switch (beneath the steering column) is involved here. It must be in the on/run setting for the wiper motor to receive power.

So, it takes two to tango: the wiper door actuated microswitch has to be intact and properly adjusted (there's a mechanical in/out adjustment to fine tune it with respect to the open position of the wiper door) AND the manual over-ride switch in the cockpit has to be intact and properly set.

Last, the wiper motor itself has to be functional and installed with proper power and ground wiring. Get all three conditions right and it ought to work, mon!

[Michael D.]

Re: '68 Wiper Switch Ground

...The wiper door mechanism opened when I turned on the wiper switch...but still no wipers.

Check here.


Wiper door has to open far enough for the plunger to trip the switch.