Home page
SPONSOR AD

Topic: 78 turn signals broken

in Forum: C3 Electrical

78 turn signals broken

Posted: 7/20/11 11:34am Message 11 of 18
Valentine
Gold Member
Send PM
Clinton Township, MI - USA
Joined: 7/19/2011
Posts: 14
Vette(s): 1978 Chevrolet Corvette 5.7L 4BL 8cyl
Turns out the flasher can was not correct.  I replaced it with a spare I had and fixed the intensity and the speed of the flashers.

I swear this is car is cursed.

When I put on either turn signal, I get instead hazards.  When I use the hazards, I get nothing.  All other lights seem to still work.

I feel like I am chasing a problem that morphs every time I think I have it fixed.  Frustration is mounting.  Give me something mechanical any day!!!

78 turn signals broken

Posted: 7/20/11 12:38pm Message 12 of 18
Profile Pic
tb2k82ce
Gold Member
Send PM
Lemon Grove, CA - USA
Joined: 10/17/2007
Posts: 2041
Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
Let me see if I have this correct you have the new switch and you have checked it for correct installation the connectors were cleaned when you put it in. You have flashers that work now that they have been installed a couple of times.  but gremlins are working in your car.  I have found that most gremlins come down to bad grounds.  Easier said than fixed because you have to find out where the ground spot is. On a Corvette this is almost as hard to do as it is a Jaguar. 

Your car is different enough from mine that I cannot help in some areas.  But just looking at the diagram that was provided I have a couple of questions.

Do the stop lights work and if so what happens when the turn signals are turned on and brake is depressed?  if the stop lights come on then your grounds are ok for the rear lights anyway. 
I can not see that there is a cross between the Hazard system and the turn signal system except in the switch.  It looks to me like the hazard disengages the turn signal system.   I would clean the flashers and check my connections on the switch.  I would also look at the wire bundle that goes to the switch and make sure it is not cracked or there does not seem to be a short. Do you have anyway to measure voltage?  even a light as we are looking at having 12 volts or nothing.

78 turn signals broken

Posted: 7/20/11 1:04pm Message 13 of 18
Valentine
Gold Member
Send PM
Clinton Township, MI - USA
Joined: 7/19/2011
Posts: 14
Vette(s): 1978 Chevrolet Corvette 5.7L 4BL 8cyl
[QUOTE=tb2k82ce]Let me see if I have this correct you have the new switch and you have checked it for correct installation the connectors were cleaned when you put it in. You have flashers that work now that they have been installed a couple of times.  but gremlins are working in your car.  I have found that most gremlins come down to bad grounds.  [/Quote]

Yes, I have all the correct equipment.  It was tediously clean with a small brush to make sure I good connections.

[QUOTE=tb2k82ce]Do the stop lights work and if so what happens when the turn signals are turned on and brake is depressed?  if the stop lights come on then your grounds are ok for the rear lights anyway. [/QUOTE]

no, my stop lights no longer work.  Not sure when that started but its new.


[QUOTE=tb2k82ce]I can not see that there is a cross between the Hazard system and the turn signal system except in the switch.  It looks to me like the hazard disengages the turn signal system.   I would clean the flashers and check my connections on the switch.  I would also look at the wire bundle that goes to the switch and make sure it is not cracked or there does not seem to be a short. Do you have anyway to measure voltage?  even a light as we are looking at having 12 volts or nothing.
[/QUOTE]

I will take everything apart and clean some more.  The wire bundle is in really good shape.  I will double check it for loose connections after this call im on wraps up.  I work from home. :)

I really appreciate all your input and suggestions guys and gals.  Electrical is not my strong suit.

78 turn signals broken

Posted: 7/20/11 2:13pm Message 14 of 18
Profile Pic
kwoody
Gold Member
Send PM
Tucson, AZ - USA
Joined: 7/11/2010
Posts: 415
Vette(s): 1982 Black/Tan Leather Build Code C09E Bronze TTop CrossFire Fuel Injection L83 85 Fuel Pump Auto Axle 2.72 Firestone Firehawk Indy500
Hi Valentine,

Also corrosion can build up at the bulb sockets and the bulb contacts.  It can increase the resistance and upset the timing circuit. It can be on the connectors where the flasher plug into. This can give you strange intermittent problems.  I use Deoxit D5 - or what ever they are calling the stuff now - by Caig Labs.  It is a contact cleaner and removes this corrosion  so you get a good clean connection.  WD-40 is not a contact cleaner. Do not spray that on anything electrical.

All the best,
Keith

Nobody ever waves when I'm driving the Explorer.
K Woody

78 turn signals broken

Posted: 7/20/11 4:54pm Message 15 of 18
Profile Pic
tb2k82ce
Gold Member
Send PM
Lemon Grove, CA - USA
Joined: 10/17/2007
Posts: 2041
Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
Having your stop lights not work is not a bad thing from the troubleshooting point of view.  We must get them working first because it is the simplest.  Battery then brake switch, turn signal switch (in its normal position) brake light bulb and ground that is it.  Unless that is working nothing else will work.  That is how it works looking over the diagram that rraider1 "Robert" provided. 

Your system is different from my 82 so that is all I have to go on.  I would say you need to find where the ground is after the stop lights.  Unless you have blown a fuse your brake lights will work 100% of the time.  (I'm assuming that the blinker control switch that you purchase is not bad.  Looking at the drawing that makes me say there is a good chance that it is that ground could be part of if not all of your problem.  It says the location is under the left end of the rear cross member. 

Do not just tighten it down.  I did that once and all it did was compress rust which is not a good conductor of electricity.  When you find it clean it and then screw it back in. 

If you can not find it or you want to check it out before you take it apart you can make a jumper out of an extension cord and connect to the ground side of the tail light and then clip it onto a good ground (I like going back to the ground side of the battery). 

I made a long set of test leads out of an outside extension cord.   I connected alligator clips to all of the ends It is about 10 feet long (I use shielded alligator clips you do not want to short them together when you have power on them). 

Now I can ground anything anywhere or provide power to anything to test it.  (the wires are not for heavy duty circuits above what ever your power cord was rated at.  I used an outdoor 20amp power cord).  Remember we are talking about test leads.

I used it to prove to myself that the window motors worked saved me a lot of time trouble shooting as it turned out to be the switches. 
tb2k82ce2011-07-20 17:01:14

78 turn signals broken

Posted: 7/28/11 6:08am Message 16 of 18
Valentine
Gold Member
Send PM
Clinton Township, MI - USA
Joined: 7/19/2011
Posts: 14
Vette(s): 1978 Chevrolet Corvette 5.7L 4BL 8cyl
Resolved!!!
Finally got to the root of this after taking a small break.  Since i had replaced the turn signal switch, I had a great octopus connector to run jumpers with. I was able to determine that the problem lie somewhere in the rear end as suggested earlier.  I was not able to figure it out however.  After staring at several wiring diagrams, I notice the switch for the break pedal.  I got under the dash and checked it and sure enough, the lights all went wonky when I played with it.  It was acting like a passthru open sometimes and was grounding other times.  Replaced it and my problem went away. 

78 turn signals broken

Posted: 7/28/11 6:11am Message 17 of 18
Valentine
Gold Member
Send PM
Clinton Township, MI - USA
Joined: 7/19/2011
Posts: 14
Vette(s): 1978 Chevrolet Corvette 5.7L 4BL 8cyl
I really want to thank everyone for the help.  This was a total learning experience and your help along the way was what got me thru it!!!  Thanks again all!!!

78 turn signals broken

Posted: 7/28/11 7:34pm Message 18 of 18
Profile Pic
Adams' Apple
Gold Member
Send PM
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20212
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Kewl!
The brake lights go thru the turn signal switch, so that does make sense.
Glad ya got it taken care of!

Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

in Forum: C3 Electrical

Our Sponsors help support C3VR