71T - can't get turn signals to work

sfoster13 · 07-03-2009, 12:15 PM

Left rear works but right rear does not. Fronts don't work either. Car had been sitting for several years. Not the bulbs, tried that. Fuse is okay. Other lights work in the rear. Could it be in the switch in the stalk? Emergency switch doesn't work either.

Zeke · 07-03-2009, 04:09 PM

It's usually a grounding issue. Check the housing to bodywork ground wires first. The ones in front attach to the battery boxes. The rear ones attach at one of the bumper bracket bolts. They are subject to rust and corrosion. If that doesn't get it, remove the housings and open the backs.

Before doing anything, check for incoming voltage to the sockets. If you have incoming, it's certainly a grounding issue.

sfoster13 · 05:13 PM

thanks milt. If it's a ground wire issue wouldn't that affect all the lights in the housing not just one? They all ground through one wire from what I can tell. Seems like a single wire grounding somewhere is the likely culprit. Problem is they're all bound in the same wire housing. Going to have to strip them apart....ugh.

Zeke · 07-03-2009, 05:30 PM

It affects lights in a funny way. For instance, if the internal ground connections are bad, like the sockets, the light on the other side will flash. Each light must be grounded individually.

I'm not an expert. Warren, (Early_S_Man) was our resident expert. If you wish to search this, use his name.

sfoster13 · 08-06-2009, 12:27 PM

okay, I'm having one of those moments when I just want to leave the damn thing on the side of the road and walk away. It degraded and started impacting all four corners so I suspected the switch or the relay.

Replaced the turn signal switch, replaced the flasher relay. Still can't get the emergency flashers or the turn signal indicators to work properly. Looking for other ideas. It's now the case that the emergency flasher relay is making the right noise when the switch is on and the relay makes the turn signal noise when the switch is selected but no lights and the relay only makes the noise for the turn signal if the emergency flashers switch is on.

A wiring issue? Things not connected the right way? Could it be the socket that the relay is connected to?

dtw · 08-06-2009, 12:37 PM

Take a deep breath and put down the breaker bar. It'll be ok.

For a sanity check, I'd turn on the t/s switch left, then right, while checking for an output signal at the fuse panel. Use a test light, if the test light is flashing, you know the switch and relay are doing their job. I'm guessing you're going to get good signals at the fuse panel.

Then there are some things you can check at the signal housings. Sometimes the spring-loaded contacts are weak and don't make sufficient contact w/the bulb. Or, the contact surfaces are oxidized and require some TLC to make good contact. If all is good at the contacts, and your grounds at each of the signal housings is in good condition, you may need to check the wiring inside the housings.

My signals have gone out on my '72, and it has always just been a matter of giving the fuse a little tweak. Back at the ranch, some cleaning and adjustment of the contact tabs solved the problem properly.

jpnovak · 01:02 PM

Whoa!

go to this page and print color versions of the 71 wiring diagrams.
http://www.pelicanparts.com/911/911_Parts/911_electrical_diagrams.htm

Don't forget the legend for the parts.

Now that you have the correct information you need to work backwards from the wiring to determine where your lights are not getting voltage. STart at the stalk with a test light or multi-meter. Then move to the fuse box. Check both sides of the fuse poles for voltage. Then work to the connector at the front firewall/fender well. Then finally out to the TS housing. If you have voltage from the ground point (negative terminal on the battery or body) yet no lights after verification of the voltage at each point then you have a ground problem as previously described.

Now while you are testing each of the connection points take them apart and clean them. Then reassemble with some silicone dielectric grease. This will keep them clean and trouble free for years.

You might want to go to the library and find a book on standard automotive wiring and trouble shooting. Electronics really scare people but they are pretty simple if you approach it in a methodical way.

sfoster13 · 08-06-2009, 12:48 PM

Quote:

Originally Posted by jpnovak

go to this page and print color versions of the 71 wiring diagrams.

I've been staring at them for days...they make me want to cry

Mo_Gearhead · 08-06-2009, 01:04 PM

Quote: "Or, the contact surfaces are oxidized and require some TLC to make good contact.'
__________________

I second this as a possible source of your problem.

Take some 1500 grit Emory cloth and twist it about a small blade screwdriver and
"scrub" all the connection ( lamp and socket ) points. Clean the bulb bases and contact ends. They may look clean - but they do oxidize over time and thus prevent current flow.

viejopatron · viejopatron's Garage

My 71T front signal electrics were all corroded in the housings. But my local old-school parts guy had good condition assemblies from a later model. $60 for the pair. I don't know what's the latest year that can fit into a 71, but this is an option.

geoff_68s · 08-07-2009, 04:28 PM

I'm feeling your pain. I just spent several weekends in a row trying to get my lights working again and the signal light circuit is the most complicated thing on the wiring diagram. Oxidation is our archnemesis it seems, and especially so in a car that's been sitting for a while. Don't know exactly why it is that if you use them, these things don't get quite so corroded up, but if you park the car for a while, then blam, every switch, connector, and socket in the car is crusty and green.

I started from the outside in, cleaning the oxidation off the bulb sockets and ground lugs with a little wire brush. That got the parking lamps and headlamps working again, but not the turn signals. Then I agonized over what to do next for a while, replaced the blinker relay with another I had around, to no avail, and then said a little prayer to the patron saints of fragile expensive things, and pulled the steering wheel and column cover to examine the switch itself. Thirty seconds after getting the switch out, it became very obvious that it would never ever go back together if I got into it far enough to find the turn signal contacts, so decided to try my luck and see if a little spray of contact cleaner would help me out. And it did.