1968 Wiper Door Pops Up
Thread Starter
Navigator
Joined: Jun 2016
Posts: 9
Likes: 0
1968 Wiper Door Pops Up
Own a '68 327/300 for the past 45 yrs. Has 56k miles. It's been in storage off/on for close to 30 yrs. Have been doing restoration work both inside/out past couple of yrs. Car runs well. A problem that recently surfaced is the wiper door has opened and closed when I'm driving. Does so on random occasions not every time I'm driving. Read other threads about wiper door issues but haven't found one with same issue a mine. Have contacted several corvette parts outfits and told it could possibly be an issue with wiper door vacuum control solenoid, wiper door limit switch, or wiper override switch. Interested in obtaining feedback from owners who may have experienced the same issue and what was done to correct the problem. Thank you!
Team Owner
Joined: Jun 2001
Posts: 23,375
Likes: 1,067
From: Virginia USA
Sounds like the solenoid attached to the back of the tach but last weekend I was adjusting my wipers after I replaced the motor and I would get the Up/Down movement after adjusting the wiper arm linkage before adjusting the wiper door vacuum safety switch that the right wiper arm parks on.
When I first bought my car my wiper door would open/close on startup and when driving while giving it WOT.
You can buy replacements for both parts but when I bought my car no vendors had the wiper door solenoid so I cleaned it using this procedure and it's worked ever since. This assumes the coil for the solenoid is still good.
Wiper Door Solenoid cleaning procedure
When I first bought my car my wiper door would open/close on startup and when driving while giving it WOT.
You can buy replacements for both parts but when I bought my car no vendors had the wiper door solenoid so I cleaned it using this procedure and it's worked ever since. This assumes the coil for the solenoid is still good.
Wiper Door Solenoid cleaning procedure
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
In most cases 1969-1972 cars that have this issue I’d say go to the wiper arm switch. But since the 1968 cars didn’t have this arm switch (relay) your issue is vacuum related.
The only way the door will open is if there is a failure on the small hose side of the system. Blocking the vacuum on the small hose side (or a vacuum drop in the system) will cause the door to open. So if you look at the schematic below, if you pulled the over-ride **** under the steering column, the door will open. It does this because vacuum is blocked on the small hose side.
So what could cause your issue.
1) Possibly a crack in a small hose either at the vacuum relay.
2) Possibly a leak in the vacuum canister on the inner fender
3) Possibly a defective part in the system. (tach solenoid, over-ride switch, vacuum relay and so on…) Check them all.
Personally, I’d probably start out with snipping about 1” from the end of all the small hoses and then re-attach. If the issue is still there then I’d start testing items on the small hose side first, then testing the larger items (actuator, vacuum tank and so on).
Willcox
The only way the door will open is if there is a failure on the small hose side of the system. Blocking the vacuum on the small hose side (or a vacuum drop in the system) will cause the door to open. So if you look at the schematic below, if you pulled the over-ride **** under the steering column, the door will open. It does this because vacuum is blocked on the small hose side.
So what could cause your issue.
1) Possibly a crack in a small hose either at the vacuum relay.
2) Possibly a leak in the vacuum canister on the inner fender
3) Possibly a defective part in the system. (tach solenoid, over-ride switch, vacuum relay and so on…) Check them all.
Personally, I’d probably start out with snipping about 1” from the end of all the small hoses and then re-attach. If the issue is still there then I’d start testing items on the small hose side first, then testing the larger items (actuator, vacuum tank and so on).
Willcox
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,221
Likes: 9,356
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
since its intermittent and happens randomly while driving and not on sstart up I would say the solenoid because its electrical and you may have a bad connection or a bad solenoid. for vacuum to randomly come on and off the crack/leak in one of the components would have to be sealed, then if you hit a bump, open then reseal itself. I dont think that would happen.
conversely it could be the signal to the solenoid that is randomly getting to it from a short or something. Unplug your solenoid and see if it happens over the next month or so. Youre not driving in the rain and if you happen to get caught out or a chance of rain in the forecast you can ""easily"" plug it back in before your ride.
conversely it could be the signal to the solenoid that is randomly getting to it from a short or something. Unplug your solenoid and see if it happens over the next month or so. Youre not driving in the rain and if you happen to get caught out or a chance of rain in the forecast you can ""easily"" plug it back in before your ride.
Last edited by Rescue Rogers; May 2, 2018 at 09:19 AM.
Thread Starter
Navigator
Joined: Jun 2016
Posts: 9
Likes: 0
theandies,
I'll check on this as the possible problem source. Will download & review the solenoid cleaning procedure.
Thank you!
Jeff
I'll check on this as the possible problem source. Will download & review the solenoid cleaning procedure.
Thank you!
Jeff
Sounds like the solenoid attached to the back of the tach but last weekend I was adjusting my wipers after I replaced the motor and I would get the Up/Down movement after adjusting the wiper arm linkage before adjusting the wiper door vacuum safety switch that the right wiper arm parks on.
When I first bought my car my wiper door would open/close on startup and when driving while giving it WOT.
You can buy replacements for both parts but when I bought my car no vendors had the wiper door solenoid so I cleaned it using this procedure and it's worked ever since. This assumes the coil for the solenoid is still good.
Wiper Door Solenoid cleaning procedure
When I first bought my car my wiper door would open/close on startup and when driving while giving it WOT.
You can buy replacements for both parts but when I bought my car no vendors had the wiper door solenoid so I cleaned it using this procedure and it's worked ever since. This assumes the coil for the solenoid is still good.
Wiper Door Solenoid cleaning procedure
Thread Starter
Navigator
Joined: Jun 2016
Posts: 9
Likes: 0
Willcox,
I will check the hoses. Given the cars age, I'm leaning toward replacing most if not all the vacuum hoses. Small cost. I'll follow your suggestion re: snipping a short end piece of the small hoses, then check the need to replace the other parts including the check valve if problem still exists.
Thank you for the technical advice!
Jeff
I will check the hoses. Given the cars age, I'm leaning toward replacing most if not all the vacuum hoses. Small cost. I'll follow your suggestion re: snipping a short end piece of the small hoses, then check the need to replace the other parts including the check valve if problem still exists.
Thank you for the technical advice!
Jeff
In most cases 1969-1972 cars that have this issue I’d say go to the wiper arm switch. But since the 1968 cars didn’t have this arm switch (relay) your issue is vacuum related.
The only way the door will open is if there is a failure on the small hose side of the system. Blocking the vacuum on the small hose side (or a vacuum drop in the system) will cause the door to open. So if you look at the schematic below, if you pulled the over-ride **** under the steering column, the door will open. It does this because vacuum is blocked on the small hose side.
So what could cause your issue.
1) Possibly a crack in a small hose either at the vacuum relay.
2) Possibly a leak in the vacuum canister on the inner fender
3) Possibly a defective part in the system. (tach solenoid, over-ride switch, vacuum relay and so on…) Check them all.
Personally, I’d probably start out with snipping about 1” from the end of all the small hoses and then re-attach. If the issue is still there then I’d start testing items on the small hose side first, then testing the larger items (actuator, vacuum tank and so on).
Willcox
The only way the door will open is if there is a failure on the small hose side of the system. Blocking the vacuum on the small hose side (or a vacuum drop in the system) will cause the door to open. So if you look at the schematic below, if you pulled the over-ride **** under the steering column, the door will open. It does this because vacuum is blocked on the small hose side.
So what could cause your issue.
1) Possibly a crack in a small hose either at the vacuum relay.
2) Possibly a leak in the vacuum canister on the inner fender
3) Possibly a defective part in the system. (tach solenoid, over-ride switch, vacuum relay and so on…) Check them all.
Personally, I’d probably start out with snipping about 1” from the end of all the small hoses and then re-attach. If the issue is still there then I’d start testing items on the small hose side first, then testing the larger items (actuator, vacuum tank and so on).
Willcox
Thread Starter
Navigator
Joined: Jun 2016
Posts: 9
Likes: 0
Rescue Rogers,
I'm gonna take your suggestion into consideration as well after I check on possible vacuum issues that may be the source. I've been told by a couple of folks that there could also be an electrical issue as well so I'll also followup on your suggestion to unplug the solenoid to see if the wipe door pops open/closes while driving.
Thank you!
Jeff
I'm gonna take your suggestion into consideration as well after I check on possible vacuum issues that may be the source. I've been told by a couple of folks that there could also be an electrical issue as well so I'll also followup on your suggestion to unplug the solenoid to see if the wipe door pops open/closes while driving.
Thank you!
Jeff
since its intermittent and happens randomly while driving and not on sstart up I would say the solenoid because its electrical and you may have a bad connection or a bad solenoid. for vacuum to randomly come on and off the crack/leak in one of the components would have to be sealed, then if you hit a bump, open then reseal itself. I dont think that would happen.
conversely it could be the signal to the solenoid that is randomly getting to it from a short or something. Unplug your solenoid and see if it happens over the next month or so. Youre not driving in the rain and if you happen to get caught out or a chance of rain in the forecast you can ""easily"" plug it back in before your ride.
conversely it could be the signal to the solenoid that is randomly getting to it from a short or something. Unplug your solenoid and see if it happens over the next month or so. Youre not driving in the rain and if you happen to get caught out or a chance of rain in the forecast you can ""easily"" plug it back in before your ride.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Navigator
Joined: Jun 2016
Posts: 9
Likes: 0
