Wiper Door Rises Then Closes at Start Up
06-24-2009, 11:03 PM
#1
Safety Car
Thread Starter
Wiper Door Rises Then Closes at Start Up
Please skip to the end and read the most recent posts unless you really enjoy reading long posts.
Ok, I've replaced the wiper relay to get rid of the hissing sound when I shut off the engine. Took care of that but the wiper door still raised slightly then shut upon startup.
So I replaced the check valve because it passed air in both directions and now the wiper door raises all the way up then closes on startup.
I went through my Dr. Rebuild vacuum troubleshooting guide but it only mentions if the wiper door or headlight raise and close after shut down not startup.
The left headlight actuator was replaced about a year ago and the other was rebuilt around the same time.
Both headlight relays are original and all of the hoses have been replaced.
What am I missing?
With the check valve not holding vacuum I thought for sure replacing it would fix the wiper door issue instead of making it worse.
Other than that, headlights and wipers work as they should.
cc
Ok, I've replaced the wiper relay to get rid of the hissing sound when I shut off the engine. Took care of that but the wiper door still raised slightly then shut upon startup.
So I replaced the check valve because it passed air in both directions and now the wiper door raises all the way up then closes on startup.
I went through my Dr. Rebuild vacuum troubleshooting guide but it only mentions if the wiper door or headlight raise and close after shut down not startup.
The left headlight actuator was replaced about a year ago and the other was rebuilt around the same time.
Both headlight relays are original and all of the hoses have been replaced.
What am I missing?
With the check valve not holding vacuum I thought for sure replacing it would fix the wiper door issue instead of making it worse.
Other than that, headlights and wipers work as they should.
cc
Last edited by CCrane65; 10-21-2009 at 09:53 AM.
06-24-2009, 11:15 PM
#3
Safety Car
Thread Starter
Ok, I'll trace all of the control hoses tomorrow and see if I can find a leak.
I guess that means I may be replacing one or both headlight relays.
Thanks.
cc
I guess that means I may be replacing one or both headlight relays.
Thanks.
cc
Last edited by CCrane65; 06-24-2009 at 11:25 PM.
06-25-2009, 12:31 AM
#4
Race Director
One very common leak in the wiper control circuit is the valve under the pass wiper arm.
Do 1 real quick check just to be sure the new wiper relay valve is not the problem.
With the engine running and headlights off and wipers off and wiper door down take a pair of needle nose and pinch the small control hose at the wiper relay and hold for a few seconds-if the wiper door pops up the diaphragm inside the relay is leaking.
06-25-2009, 10:07 AM
#6
Safety Car
Thread Starter
That is one of the problems with this system is that the control circuit for the headlights is connected to the wiper control circuit so one does effect the other.
One very common leak in the wiper control circuit is the valve under the pass wiper arm.
Do 1 real quick check just to be sure the new wiper relay valve is not the problem.
With the engine running and headlights off and wipers off and wiper door down take a pair of needle nose and pinch the small control hose at the wiper relay and hold for a few seconds-if the wiper door pops up the diaphragm inside the relay is leaking.
One very common leak in the wiper control circuit is the valve under the pass wiper arm.
Do 1 real quick check just to be sure the new wiper relay valve is not the problem.
With the engine running and headlights off and wipers off and wiper door down take a pair of needle nose and pinch the small control hose at the wiper relay and hold for a few seconds-if the wiper door pops up the diaphragm inside the relay is leaking.
I also pinched the feed to the headlight relays and it stayed shut.
I'll remove the wiper grille and test the valve there next.
cc
06-25-2009, 01:27 PM
#7
Safety Car
Thread Starter
Didn't find anything wrong with the wiper park switch.
For the time being I'll put my old check valve back in so the door will only raise slightly then close instead of going all the way up and down.
cc
For the time being I'll put my old check valve back in so the door will only raise slightly then close instead of going all the way up and down.
cc
06-25-2009, 02:47 PM
#8
Team Owner
I ran with no vac tank as it was shattered with metal fatigue....
07-02-2009, 09:14 AM
#10
Race Director
The control on the top of the relay is just a small diaphragm and it just needs to hold vacuum. If you have a Mighty Vac gun just pump it up and watch the gauge to see that it HOLDS vacuum.
If you dont have a Vac gun then use the same test that you used on the wiper relay--- with the engine running and the headlights down with a pair of needle nose pliers pinch the small control hose about an inch away from the relay and hold---if the diaphragm is leaking internally the headlight will pop up.
07-02-2009, 11:42 AM
#11
Safety Car
Thread Starter
Since your headlights go up and down we know relay is functioning.
The control on the top of the relay is just a small diaphragm and it just needs to hold vacuum. If you have a Mighty Vac gun just pump it up and watch the gauge to see that it HOLDS vacuum.
If you dont have a Vac gun then use the same test that you used on the wiper relay--- with the engine running and the headlights down with a pair of needle nose pliers pinch the small control hose about an inch away from the relay and hold---if the diaphragm is leaking internally the headlight will pop up.
The control on the top of the relay is just a small diaphragm and it just needs to hold vacuum. If you have a Mighty Vac gun just pump it up and watch the gauge to see that it HOLDS vacuum.
If you dont have a Vac gun then use the same test that you used on the wiper relay--- with the engine running and the headlights down with a pair of needle nose pliers pinch the small control hose about an inch away from the relay and hold---if the diaphragm is leaking internally the headlight will pop up.
Any chance the wiper solenoid is causing this? Since it is the most difficult component to get to it's probably going to be the source of the problem.
cc
07-02-2009, 12:07 PM
#12
Race Director
Sure its possible. Its even possible the leak is in the headlight switch or one of the pulldown bypass switches or actually anything that is on the small hose can bleed it off--the wiper door always reacts first.
In your case you can trace this backwards from the wiper vac relay using clamps until you isolate the problem. Try the pinch test on the wiper relay again and then go from there.
In your case you can trace this backwards from the wiper vac relay using clamps until you isolate the problem. Try the pinch test on the wiper relay again and then go from there.
07-02-2009, 02:21 PM
#13
Safety Car
Thread Starter
Sure its possible. Its even possible the leak is in the headlight switch or one of the pulldown bypass switches or actually anything that is on the small hose can bleed it off--the wiper door always reacts first.
In your case you can trace this backwards from the wiper vac relay using clamps until you isolate the problem. Try the pinch test on the wiper relay again and then go from there.
In your case you can trace this backwards from the wiper vac relay using clamps until you isolate the problem. Try the pinch test on the wiper relay again and then go from there.
So I moved into the passenger compartment and took the steering column trim plate off so I could get the override switches down then pinched the wiper door override switch control line and the door opened. I assume that is normal. That line also seems to go to the wiper solenoid but I am going by feel since I can't see up there.
Let me know if my assumptions are correct to this point. Not sure how to go about testing the wiper solenoid though.
cc
07-02-2009, 05:13 PM
#14
Race Director
Normal if you have a LEAK between the vacuum source and the wiper relay valve. Once your system is leak free you should be able to pinch any control line and nothing will happen.
Go back out to the firewall with your pliers and find the 3 small hoses that go through into the wiper area and attach to the control valve under the right wiper arm. With the engine running pinch the red stripped hose (red stripped hose goes to center port on the control valve)on the engine side of the firewall. If the door pops up the control valve is leaking. Could be bad or misadjusted,try pushing the wiper arm down further and try the test again.
Go back out to the firewall with your pliers and find the 3 small hoses that go through into the wiper area and attach to the control valve under the right wiper arm. With the engine running pinch the red stripped hose (red stripped hose goes to center port on the control valve)on the engine side of the firewall. If the door pops up the control valve is leaking. Could be bad or misadjusted,try pushing the wiper arm down further and try the test again.
07-02-2009, 05:14 PM
#15
CC
I'm watching this thread closely because I have the same problem...the wiper door opens fully and then closes on startup. The leak down is quite rapid. I've replaced everything except the tank and the headlight actuators (or seals) and the headlight relay. The tank is currently out of the car so I will test it separately.
The problem is definitely on the control side.
FR
I'm watching this thread closely because I have the same problem...the wiper door opens fully and then closes on startup. The leak down is quite rapid. I've replaced everything except the tank and the headlight actuators (or seals) and the headlight relay. The tank is currently out of the car so I will test it separately.
The problem is definitely on the control side.
FR
07-02-2009, 05:30 PM
#16
Team Owner
Member Since: Sep 2006
Location: Westminster Maryland
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Hi CC ad FR,
DW has been giving you THE good advice.
I found that Dr. Rebuild's Trouble Shooting Guide is worth the few $ it costs. It tells you how each component is supposed to work and how to test each component with a tool like a Mighty-Vac.
The fact that both systems are combined on the control side, as DW pointed out, makes it tough to locate a slow leak.
Good Luck!
Regards,
Alan
DW has been giving you THE good advice.
I found that Dr. Rebuild's Trouble Shooting Guide is worth the few $ it costs. It tells you how each component is supposed to work and how to test each component with a tool like a Mighty-Vac.
The fact that both systems are combined on the control side, as DW pointed out, makes it tough to locate a slow leak.
Good Luck!
Regards,
Alan
07-02-2009, 05:42 PM
#17
Race Director
Thanks Alan I know you have worked on your fair share of these. Imagine how much easier this would be if GM would have separated the 2 sides and then if they would have separated the wiper control from the headlight control. But then we wouldn't have all these fun problems to solve.
07-02-2009, 07:26 PM
#18
Melting Slicks
Maybe this is why Chevy got rid of the wiper door. I have always wondered what owners of 68-72 corvettes do if the wiper door fails when it is raining. Do they have a override switch for it like the headlights?
07-02-2009, 09:04 PM
#20
Race Director