1968 w/wiper trouble shooting

[James S.]

Having trouble with wiper function early production car (Oct 68) !!!! Is there a step by step system check that anyone has to verify electrical, vaccium and machanical operations ???? I have bench tested wiper motor and it appears fine ...

[Michael D.]

Re: 1968 w/wiper trouble shooting

What type of problem? Wiper door won't open? Wipers don't run?

[Jim T.]

Re: 1968 w/wiper trouble shooting

James is the electical switch at the bottom of your driver dash in the correct position?

[James S.]

Re: 1968 w/wiper trouble shooting

Hey Micheal !!! Thanks for your interest, Brief discription of existing state: Start vehicle - no function at center dash switch wipr,washr or door. Override Switch Opens & Closes door but no wiper operation. Can hear and see coil activate washer release but no movement on wheel cam ... Jim

[James S.]

Re: 1968 w/wiper trouble shooting

Hey Jim !!! Thanks for your interest, what do you mean by right position ???? The wiper control opens and close the wiper door up/down. Headlight control opens and closes the headlights. The round knob doesn't appear to have any effect ???? Jim

[Roger O.]

Re: 1968 w/wiper trouble shooting

The 68 is a one year only wiring wonder.
However all C3s must have a good ground of the wiper dash switch , because the only thing the switch does is ground in varying degrees.
Is your dash cluster frame broken in the usual spot ?
I always recommend running a temporary ground wire from the actual dash switch to a good known ground until you work out whats wrong.
Very often especially on a 68 there are several problems.
I've only worked on a few 68 wipers and most were worked on by bubba.
Here is a 68 only help paper , if you have questions I'll try to answer them or try to get answers for you.http://willcoxcorvette.com/instructi...0_rev_2_03.pdf

[Jack H.]

Re: 1968 w/wiper trouble shooting

The wiper switch in the center console IS the primary actuator for the wiper/washer system as the headlight switch is for the headlights. BUT, on Shark cars (it was pointed out that '68 was unique, what's new?) there are master over-ride controls for BOTH systems below the steering column.

These are covered in your copy of the owner's manual, but in short there's a pull down vac switch that FORCES the headlight buckets to open and stay open (purpose: allow maintenance for the headlights).

There's another pull down vac switch that FORCES the wiper door to open (purpose: allow access to wiper arms AND for convenience of driving under light mist conditions when you want to periodically 'pulse' the wipers).

Last, there's an electrical switch with 'turn knob'. It's purpose is to cut OFF electric power to the wiper motor to 'freeze' the wiper arms and facilitate changing wiper blades.

The later is what prior posters questioned. Could it be your wiper motor doesn't start/run because the master over-ride switch is mis-set? That's the gist of the query...

[Terry M.]

Re: 1968 w/wiper trouble shooting

Last, there's an electrical switch with 'turn knob'. It's purpose is to cut OFF electric power to the wiper motor to 'freeze' the wiper arms and facilitate changing wiper blades.

The later is what prior posters questioned. Could it be your wiper motor doesn't start/run because the master over-ride switch is mis-set? That's the gist of the query...

Back when I was 1970-72 Team Leader during the operations check we used to "cure" a lot of non-functioning wipers by advising the operator to turn that knob. It is pretty easy to turn it while cleaning the car and not realize you have done it. Then there are those who have no clue what that knob is for.

[Roger O.]

Re: 1968 w/wiper trouble shooting

I've been told (cant confirm ) that when the knob is in the off position on a 68 it will run the battery down. I'm not too bad with diagrams and understanding them but I have not mastered the 68 wiper wiring.
I will say by looking at the 69-72 diagram that can not happen if wired correctly.

EDIT- probably should add-some have said the knob cuts the power or 12v + to the wiper motor-this is true on 69-72.... BUT ..on a 68 the knob cuts "A" ground through the limit switch to something inside the motor (this is not the motor case ground going to the blower motor).

[Jim T.]

Re: 1968 w/wiper trouble shooting

James it is possible that the plastic knob that is mentioned is missing and all you can see is the switch stem.

[James S.]

Re: 1968 w/wiper trouble shooting

James is the electical switch at the bottom of your driver dash in the correct position?

Hey Jim it sure is !!!!!