I have turn signal issue on a 68 Chevelle. They used to work but don't now...

The fuse looks OK, the hazards work fine, but no turn signal right or left and no indication on the dash. I figure if the hazards work, then the wiring, fuses, and bulbs are OK. So its got to be the flasher relay or the turn signal lever on the steering column.

Could this be caused by the turn signal flasher relay under the dash (I know that the hazard flasher is located on the fuse box) ?

My wiring diagrams in the 68 Service Manual don't give me much info on how to actually debug this issue.

Any help is appreciated,
Richard

I have turn signal issue on a 68 Chevelle. They used to work but don't now...

The fuse looks OK, the hazards work fine, but no turn signal right or left and no indication on the dash. I figure if the hazards work, then the wiring, fuses, and bulbs are OK. So its got to be the flasher relay or the turn signal lever on the steering column.

Could this be caused by the turn signal flasher relay under the dash (I know that the hazard flasher is located on the fuse box) ?



Any help is appreciated,
Richard
I believe the two (flasher, turn sig.) relays are the same. Try swaping them and see if your signals start working. If so, Replace it...

Check that there is 12v to the pink wires on the flasher with the key on. There should be 12v coming out of the flasher on the purple wire. If not, the flasher's bad.
Current is fed from the fusebox down the pink wires, to the flasher, and into the T/S switch on the purple wire out of the flasher. The T/S switch directs the current to the left or right side bulbs and to the dash indicator bulbs.
BillL

I checked the voltage on the pink wire - 0 volts. I put one voltage lead on the metal lead for the pink wire and the other lead on the ground terminal at the base of the steering column. (there was no voltage on either wire).

I did notice that the black wire on the base of the steering column is broken and I have no idea where it goes. Could the problem be the broken ground wire even though the hazards work.

Man, you have to be a contortionist to work under the dash with a muncie stick spearing your back.

OK, looks like the black wire at the base of the steering column was added when the previous owner added a new radio. I removed the radio wiring to simplify things.

Still no voltage at the turn signal flasher taken with the positive lead on the wire and the negative lead on nearby metal steering column(or anything else that is metal). I don't know what to use for ground other than nearby metal-frame ground.

I can replace the signal flasher, but that isn't going to solve the problem I believe. I measured the resistance of the signal flasher and it measured infinity (basically an open).

I checked the fuse again for the turn signals - looks OK other than the fuse terminals are a little rusted.

Are there any grounds that are particular just to the signals ? Any ideas ?

You have to have voltage on the pink wire to the flasher with the key on in order for the turn signals to work.
Use your voltmeter (I'd buy a test light if you don't have one, it's easier to see a light come on than trying to read voltage on a meter) to check the DIR SIG/BACKUP fuse, next to the bottom on the right side, with the KEY ON to see if the fuse is good on both sides. If it checks good, find a 12ga (big) pink wire coming out the top of the fusebox into the instrument harness-that's the wire to the flasher. Turn the key off, pull the DIR SIG fuse, use an ohmeter to check for continuity on each end of the pink wire. If the wire is broken, or if the connection on the back of the fusebox is bad, that's the problem. You can pull the fusebox (2 5/16" screws, at diagonal corners) and separate it from the bulkhead connector to look at the back side.
If you'll remove the seat it makes it easier to get under there and work.
BillL

OK, thanks for the help. I really like your straight-forward debug steps.

I'll purchase a test light tomorrow -- most stores are closed today. I'll let you know what I find out.

Are there any grounds specific to the signal flashers. In reading the archives, they mention a ground attached to the e-brake and a ground in the trunk. Would you think the hazard flashers work and the turn signals not if one of these grounds were bad ?

Are there any grounds specific to the signal flashers. In reading the archives, they mention a ground attached to the e-brake and a ground in the trunk. Would you think the hazard flashers work and the turn signals not if one of these grounds were bad ?

Not really, flashers work by the current load going through them. The only grounds they're concerned with are the grounds for the bulbs. If the bulbs don't have a good ground, they don't come on, and the current load at the flasher is reduced.

The ground wire at the e/brake is to ground the dash cluster. If you have dash light or gauge problems, that's one of the first places to look.

The only ground at the rear of the car is under the car where the fuel gauge ground wire is screwed to the trunk panel. The bulb are grounded by the clips on the bulb sockets. If there's a lot of paint or corrosion where the bulb sockets pop into the taillight housings, clean it off and put a little dielectric grease or copper-based antisieze on the housing to make a good ground. You can also gently bend the clips to hold the sockets in tighter. Be careful, they break easily.
BillL

I believe the two (flasher, turn sig.) relays are the same. Try swaping them and see if your signals start working. If so, Replace it...
X2 on this technique if you haven't done it yet. Otherwise, listen to BillL. And definitely pull the seat to work under the dash. Totally worth it. :yes:

I believe (and I may be wrong) that there are two flasher/signal relays.
One on the fuse box and another at the bottom of the metal frame that supports the dash bezel. The flasher is held on the metal frame by a U shaped clip.

Here is a picture of the flasher under the dash, this picture was taken prior to mounting the U shaped clip that holds the flasher in place. So the part is just hanging there until I finished working on the radio.

Latest update:

Bought a "continuity tester" (for non-active circuits) and checked the continuity from the fuse box along the pink wire to the connector for the flasher relay -- checks good

Also bought a "test lamp" (for active circuits), used the metal of the brake petals mount as ground, checked each side of the fuse (2nd from bottom on right side) and checked the pink wire at the connector -- ALL check good

Using voltmeter at each of the above points measure 11.88 volts

Bought new hazard relay and turn signal flasher relay - still only hazards work

Probed the new turn signal flasher relay with the "test lamp", pink wire side lights the lamp brightly, purple side lights the lamp VERY DIM -- turn signal flasher doesn't work

I would guess a ground problem, but the hazards work so I'm stumped...

Any more ideas ?

Make a jumper wire, unplug the flasher, use the jumper to connect the pink and purple wires at the flasher connector. Turn the key on, turn the turn signal switch to one side, see if the bulbs on that side light up. Do the same with the other side. This test will tell you if the current is going through the t/s switch to the bulbs.
BillL

I took the old flasher relay and removed the plastic top and soldered the metal together and plugged it in.

Left front & rear turn signals bulbs light (of course no flasher, which is expected)
Right front & rear turn signal bulbs light.

So we know that current is going thru the t/s switch to the bulbs.

I had bought one flasher relay from O'Reilly autoparts and one from NAPA. Willing to try anything, I swapped the two flasher modules and the turn signals left and right WORK now but not forever. In other words, if I chose the right turn signal, it will blink about 10-15 times and then stop. Once it stops, the left won't work either.

At one time, I had the left and right working about 10 times each. What could be causing the intermittant flashing. Do these parts need to work above 12 volts which would explain the intermittant operation (I measured 11.80) ?

Did some more checking, if I use the "special" direct-wire module I made to bypass the flasher relay, the turn signal light sometimes work and sometimes doesn't. Right now with the direct-wire bypass, the turn signals don't work -- nothing at all.

Man this one is frustrating, one minute things work the next minute they don't...

Sounds like an intermittent bad connection on the t/s switch power wire.

Pull apart the "C" shaped connector for the turnsignal switch and inspect the terminals closely, use a flashlight and glasses if you don't see well (like me). Be sure none of them have backed out or are corroded. Clean with contact cleaner & plug it back. Check for current on both sides of the connector at the purple wire with the key and t/s switch turned on.

Bad switch contacts?? Wiggle on the t/s lever while it's turned on and see if that does anything. Pull the steering wheel & look at the switch, see if anything looks broken, spring out, contact arm broke, etc.


I'll try to find time tonight to make a diagram of the switch wiring and post it.

BillL

I removed the steering wheel and got to the turn signal switch.
I cleaned up the contacts on the turn signal switch and re-installed it. -- Turn signals still don't work.

Couple of questions:

1.) Does anybody know how to continuity test my t/s switch to see if it is good or bad ?
2.) Does anybody know where to get the t/s switch(for 68 Chevelle) ? O'Reilly(part S3249 or D6211) and NAPA (part DL6194) seem to have something similar but with some different connectors ?
3.) Does anybody have the wiring diagram for the t/s switch ? There are eight wires mounted on a semi-circle connector. If I had the wiring diagram, I could do a continuity test from the flasher connector to the connector for the t/s switch.

thanks

Turn signal switch connector wiring-
Terminal 1-12ga White from the "cold" side of the brake light switch.
2. 20ga Dark green, to 8 pole connector under dash above the fusebox-through this connector to RH stop/signal bulb.
3. 20ga Yellow, to 8 pole connector under dash above the fuse box-through this connector to LH stop/signal bulb.
4. 12ga Purple, from turn signal flasher.
5. 12ga Brown, from hazard warning flasher in fuse box.
6. 2 20ga Dark blue wires, one goes forward through terminal D-T on the bulkhead connnector then to the front RH signal bulb. The other wire goes to the RH t/signal lamp in the dash.
7. 2 20ga Light blue wires, one goes forward through terminal D-S on the bulkhead connector then to the front LH signal bulb. The other wire goes to the LH t/signal lamp in the dash.
8. 20ga Black wire goes through terminal A-T on the bulkhead connector and plugs into the horn relay.
Summary--
White wire is powered when the brake light switch is activated.
Purple and Brown wires are power from the flashers, brown is 12v at all times, purple, when key is on.
Dark green is RH rear bulb, dark blue is RH front bulb and dash indicator.
Yellow is LH rear bulb, light blue is RH front bulb and dash indicator.

Continuity testing the switch-
1. Have the t/signal lever in the middle position (off). Separate the switch connector-there are locking ears at each end of the "C" that need to be released to get the connector apart.
2. You will be testing the wiring that goes to the turn signal switch, not the harness wiring.
3. Connect one end of the tester to the wire that the purple harness wire connected to, it may or may not be purple in the switch harness.
4. Connect the other end of the tester to the wire that the dark green harness wire connected to-there should be no continuity.
5. Lift the turn signal lever-there should be continuity. Test the wire that the 2 dark blue wires connected to-there should be continuity.
6. Pull the turn signal lever down and test for continuity between the purple wire and the yellow wire and then the two light blue wires. There should be continuity with the switch on, none with the switch off.

You have said that the 4-way flashers work, do your brake lights work correctly??

Question 2-Ground Up part #GRT-304 says "67-68 all", NPD Part # C-2895-5A says "67-68 W/o tilt, "DELCO-REMY",repro" part # C-2895-2 says "67-68 w/column shift, 2pc harness or cast "DELCO-REMY" "67-68 owners: Check your orginal casting for "DELCO-REMY" or "BOYNE" before ordering.", Ausley's part#ES6211 says "1967-68 Turn signal switch w/o Tilt.
I'd look your switch over carefully and make some calls to be sure you get the right part, if you need one.

BillL

BillL, I am grateful you are on this forum. I really appreciate the time you spent on this info. I'm going to continuity test my part to see if it appears faulty or intermittant.

Brake lights work and 4-ways hazards work.

I have the steering w/o tilt and is the Delco-Remy "D" type. If the part is not a "D" shape then it is the BOYNE style. My part appears to be much like GroundUp part "GRT-304" except that they provide another connector to handle the 69 chevelle style. If I end up getting that part, I believe I just clip the rectangle connector together and then use the "semi-circle" connector to plug into my harness.

thanks again

OK, I tested the continuity on my turn signal switch.

The 68 Chevelle has 8 wires on the semi-circle connector: black w/white stripe, solid green, black w/yellow stripe, solid purple, solid brown, solid dark blue, black w/lt. blue stripe, and solid black.

With the ground clip on the solid purple wire(from t/s flasher relay):

1.) lever middle -- no other wires have continuity
2.) lever up -- dark green and dark blue wires have continuity
3.) lever down -- black w/yellow stripe and black w/lt. blue stripe wires have continuity

Based upon what BillL has provided above, I would assume that this switch is OK. Is this a good asumption ?

I guess I need to test continuity from the t/s flasher relay to this wiring harness on the turn signal switch. Any other suggestions ?

Just let me interrupt briefly here, as BillL is also teaching ME about 68 wiring, so I do not claim to be the expert.

Make sure the cluster is grounded. There's a ground at the top-left side of the cluster (part of the headlight and wiper switch mounting bracket), and another on the ignition switch mounting bracket. The lights ground to the cluster, but if the cluster isn't grounded, neither are your lights. These grounds use star washers if I am not mistaken. The ground at the top left of the instrument bezel is a common problem, because people hate to crack the bezel by tightening that screw. I have added extra grounds to my cluster simply because of all the problems I've read about grounding these 68 gauge clusters.

The fact that switching the blinkers caused the lights to work briefly does suggest a poor contact but aren't there also "electronic" versus "contact-style" blinkers? One or the other might be more sensitive to the voltage you describe. Are you doing any testing with the car running?

Good luck, my hazard flasher is busted so this is all relevant to a project coming up very soon.

I have tried the same testing with the car running with no better results.

I'll check my grounds on the cluster and maybe add a few more grounds. All along, I suspected it might be a "ground" problem but I was having a hard time getting a handle on it.

I'll try these things this coming weekend now that I'm becoming more adept at using the continuity tester and test lamp tester.

Since I had the steering wheel off, I replaced the turn signal switch with a new one from M & H. The approximate cost is $34.00, very nice stuff and I believe they are the least expensive and other vendors just carry their product. It came with a small light attached so I just clipped that wire off because my wiring harness only supports 8 wires. Lession here is take lots of pics and write down what you disassembled on paper, because it took lots of looking at an assembly manual to figure how to put it back together.

Bottom line was it didn't fix the problem with the turn signals but I aready knew that since my original checked out OK. I then checked the grounds and they looked OK. I then took the fuse box apart after probing the front with a test lamp and found no power on one side of the fuse. The wire on the back was good & tight and had power. I then pulled the fuse again and accidently put it back in half way -- turn signals work ! There appears to be a bad contact for the turn signals, I cleaned them up, but still a bad connection if the fuse is pushed in all the way. I'll have to eventually replace this fuse box.

But for now, I have turn signals again and thanks to all the forum members who helped.