Full Size Jeep Network

I'm having intermittent issues with my turn signals not working all the time. They seem to work fine when parked (but not always), and tend to fail more often at faster speeds.

Thought I'd check my grounds but I'm not sure where I should be looking? The TSM says the cluster ground is at the directional flasher at the lower left of the panel. I'm not seeing that. I have something similar on the firewall, near the floor parking brake, but I'm missing the ground wire that the TSM is showing. Any suggestions?



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The ground wire does not affect the flasher unit. It's got to be for some other ground, and the bracket screw is a convenient place to put it. Cluster ground, not flasher ground. Suggest you look for that ground wire on the schematic. Look at the '72 diagrams, or '73.

The flasher does not need ground. It will work (or not) with or without the bracket, even hanging free. There is a bimetal strip in the flasher. It conducts, heats up and contacts opens. It cools and contacts close. Repeat as needed. Control is in the turn signal switch - if not the flasher, that's likely where your problem is.

Also mention - intermittent operation of the indicators at the bulbs can affect the flasher. Bulbs open or intermittent ground, no current flows and no flashing.

The cluster ground is terminal D to connection 8 on the '72 diagram, page 22-17.

Also check corroded harness connections, which are common for an old car. Dash harness, frame harness, and chassis harness plug together and should be unplugged and cleaned. Loss of continuity will interrupt flasher operation. Suggest contact cleaner and a stiff plastic brush, initially.

Deoxit D5 works well, but is expensive. Includes 5% oxide cleaning chemical plus the usual solvents. Plain contact cleaner only has solvents, and evaporates completely. A touch of dielectric grease on the connectors is an excellent precaution, but has no cleaning/curative effect.

I'll just put my $0.02 in here. Have had the exact problem over the years with Jeeps. To me, it's been the flasher most often. I just went through a box of about 30 units I had picked up at swap meets etc and had thrown in a shoe box. Most were probably used and had been swapped out (but kept???) but a few still in boxes. The flashers that looked like silver metal cans were almost always bad-despite looking shiny and new. Strangely, the cheap looking light blue TUNG-SOL types were almost all good (despite them looking dirty).

I also went through several "heavy duty" type flashers over the years and most of these had to be rapped on the bench before they worked. The one in my Wagoneer recently was similar. If I rapped it or hit it hard, it would work fine for days but then stop randomly. For now, I have a real old looking TUNG-SOL in a orange plastic can and it seems to be working.

As Tim says though, grounds can be issues too. Clean up all the grounds and add more if you can. Also, don't over look the bulb and sockets themselves. The corrosion can make them operate intermittently.

Good luck!

On my 76 J10 the rear lights.. parking. Brake.. flasher and side front flashers.. all rely on the body to ground them.

Well the front side flashers have a ground wire. But still.

Check all the grounds. And create new one. And unscrew lights snd clean corrosion off terminals

There are flashers (bulbs) that flash, and the flasher relay that makes the on/off flashing current, under the dash.

The round flasher relay that the OP shows is mechanical and its case does not require a ground. This is what these Jeeps came with from the factory. There is a relay for the indicators (turn signals) and a relay for the hazards (4-way emergency flashers).

Some electronic/transistorized replacements for the original relays require a ground wire. The flasher lights themselves require a ground, at each corner of the Jeep. These will be grounded to the body, either through a wire for plastic fixtures like the clearance lights, or through the metal housing like the front turn signals or the tail lights.

If the grounds at the corners are not good, the mechanical flasher relay may not cycle.