Hello all,

I have a 77 F100 Ranger XLT that I have been trying to trace down the blinker issues with. I did search this forum and read all of the previous blinker threads but I haven't found any that specifically reference this.

There was some blinker activity when I bought the truck. The tail light blinkers were initially working after some replacing of bulbs and harnesses. Eventually they were all working except for the driver side front. I have now replaced this bulb housing too. The strange thing is they would only work when the headlights and/or parking lights were turned off.

They have no graduated to not working at all!

I have replaced the ancient flashers that were in the truck with new ones. The hazard lights do work, I have rotated both flashers to make sure I did not end up with another bad flasher. I am assuming the steering column is getting power because the hazard lights button is causing some action.

I have been using the chilton wiring diagram (from the online chilton library) to try and trace the wires but I keep running into a dead end. The chilton diagram shows there is a "DIRECT" fuse for directional flasher. It has a an orange/white wire (I think, writing from memory here) that is suppose to run to that fuse. My truck has no DIRECT fuse. This slot is completely empty in the fuse box, and looks as if there was never a fuse there in the history of the truck from the factory. The orange/white (or orange/yellow) wire runs into a harness in the dash the best I can tell so I am not sure if there is an inline fuse or something else elsewhere.

At this point the flasher is showing no power with a test light. The parking lights are getting power on both power wires. There is no blink.

Any ideas? It has become very frustrating!

Thx in advance for your help!

 

Truthfully ..... it sounds like a poor ground to me but it could be something else.

All you can do is trace wires. Trace them to where they enter a wrap, follow the wrap, and find where they exuit, look for damage along the way.

Also check grounds. At each bulb socket, check the ground side lead. At each bulb spot, with switch on, use a test light to test for power between the hot side and a good solid ground.

The wires are old, the copper is likely OK but you will likely find cracked dry hard insulation in places. You can wrap in a good quality electrical tape but you'll loose the color code if you completely wrap one where visable.

Time consuming work.

 

tbear thx for the reply. I have tried to trace the wires but it gets hectic. The blinker flasher is no longer clicking at all (it use to) so I am assuming the power is dropping out before the blinker flasher.

I am still confused why my truck has no "DIRECT" fuse but the Chilton diagram shows there should be one. Its as if my blinkers are not on a fuse at all..

 

Often times, when there is interaction between the headlights and the turn signals, there is a ground issue at the bulb socket itself. This is because both filaments in the dual-filament parking light / turn signal bulb share a common ground. Current through one filament (via the parking lights) lowers the voltage headroom for both filaments because of a ground shift - but turning the lights off lets the turn signals work since the ground is closer to "true ground" in this case.

Now, however, you're saying you don't have them at all. That's interesting about the turn signal fuse location being empty in your truck - I have seen this on other Fords as well. My '73 Galaxie has the same thing (turn signal fuse is empty and has no fuse connectors) while my '77 LTD had it populated. So I do know that there have been Fords with an unprotected turn signal circuit which is a design flaw. However I'm not up to speed on whether or not this is the case for trucks.

When you checked for power at the turn signal flasher, did you check for power with the key in ACCessory or RUN? Did you check both terminals in case you picked the wrong one the first time? Do the other accessory circuits (like the radio, wipers, etc) work?

 

I checked with the key on turned to the left and the right, as well as with the truck running. I checked both terminals on the flasher. I swapped the flasher out with the hazard flasher and tested this way as well. I did all this testing after replacing both flasher's with brand new ones. I tried both terminals of the directional flasher during the test.

I originally thought maybe the power was not getting to the steering column but the hazard button is functioning. In addition to that, although my truck has been converted to have the automatic shifter in the floor, it was once upon a time on the steering column. The light in the column that was intended to light up the gear indicator still lights as well.

Originally the directional flasher did click, but that has sense ceased when the blinkers stopped working outright. I am unclear on where the directional switch in the column actually "gets its power" from. The wiring diagram is unclear to me on this point. I am unclear on where the directional flasher gets its power from since its not actually running into the fuse box as shown in the diagram.

I am not sure if the radio circuit works because there is currently no radio in the truck and I have not tracked down the wires that would connect to the radio yet as I have had other more pressing issues (like blinkers!), however the windshield wipers do work.

The instrument panel has issues as well, i.e. when the blinkers were working, they were not actually blinking on the instrument panel-

I am at a loss as to why they didn't run the directional flasher on a fused circuit in this truck when apparently that was how it should be according to the diagram. I thought at first someone may have ripped out the fuse and just bypased it, but looking closely at that fuse box, there is no tampering or obvious history of there ever being any connection or housing in the "DIRECT" place.

 

Power to the flasher does not go through the column, but power from it does. 12 volts is applied to one side of the flasher, then the other side of the flasher runs up through the column, to the turn signal switch. When the turn signal switch is closed in either direction, the signal from the flasher is routed back down the column to the appropriate side of the truck, where it runs out to the bulbs, and also up to the dash for the indicators. In other words, the flasher should receive power before the column even comes into the path.

By chance are there any other blown fuses in your fuse panel? Maybe your flasher is powered off another circuit for some reason. I'm at a loss as to why your flasher isn't receiving power if there's no fuse in the path - at the end of the day you could always trace upstream, but that's not very easy considering everything is bound together very tightly in the wiring harness.

If your wipers work, then that takes the ignition switch out of the equation.

 

That is some very good insight. If power runs from the flasher to the column, then that means that the power drop out is happening somewhere behind the flasher, not in the column as I had thought previously.

I did check all of the fuses and the radio fuse was blown, but I bought a fresh batch of fuses at advance auto last night and replaced the radio fuse. All other fuses are good.

I had previously tried to follow the wires from the flasher (because they didn't go to the fuse box I was curious where in fact they did go) but as you have stated the wire that should be carrying power > to the flasher, runs into a tightly bound mess behind the dash.

I guess at this point I should just pull all the lights and test the connects again, but I am not sure if that is the right next step since they are all flashing appropriately when the hazard is triggered leading me to believe that the connections are good

Another thing that just occurred to me- could I just pull 12V off the ignition and run it straight to the orange wire on the flasher? That would then power it up and allow power to go through it and up to the column ?

 

If the turn signals are not blinking because they're not receiving power, then you're correct. However, of all the reasons for turn signals not to work, the one that seems to be the case at this point is the least common. Although, if you're not receiving power in the first place, then you're not receiving power. But it's uncommon for wiring that is tightly bound in the wiring harness to all of the sudden stop conducting - usually something has to burn for this to happen.

That's correct - if the problem is in fact that the turn signals are not receiving power, then applying 12 volts to the ORANGE/YELLOW wire (where 12 volts would normally be supplied by the fuse panel) would effectively bypass the issue, and the turn signals should work.

Note: I highly recommend using a jumper wire with an inline fuse (15 amp according to my wiring diagram) to perform this experiment; I would not use a straight wire. At this point, you don't know why the turn signals are not working - and there could be a short to ground somewhere in the circuit that's not obvious at this point. Anytime you perform any kind of testing that bypasses the fuse panel, you must use some form of circuit protection, since it's not particularly clear what the problem is at this point and it's not clear what you'll find. As I'm sure you're well aware, a car battery will source as much current as it can until whatever is downstream of it burns up. Furthermore, the fusible link at the start of the electrical system (near the starter solenoid) is only sized to protect the heavy-duty wires to and from the ignition switch - it cannot protect the smaller gauge wire downstream.

This is just a sanity check - but have you verified that the test light is grounded properly? Sometimes I've tried to use it under the dash, and it wasn't working because I was clamping to painted metal by accident. Have you tried probing a known-good circuit that you know has power, just to make sure the test light works and the ground is good?

 

Well it never got to the point of jumpering the flasher but your sanity check below is good advice!

I solved the problem with your help. The conversation here got me thinking it was time to start from the beginning and go back through everything.

So I checked the fuse box, and there was in fact a fuse missing. How I missed this I don't know. My buddy missed it too because he was messing with the fuse box last night and we were both scratching our heads about why the blinkers were not working! The fuse in question was above the radio fuse. I cant really read what it says but its not the wiper fuse as seen on my wire diagram as the wipers never quit working.

I replaced this fuse, flicked the blinker and the flasher clicked a few times and stopped. The fuse I put in there was 15 amp, so I put a 20 in (big risk taker! =) The flasher clicked longer this time and then stopped again. I was running out of fuses at this point but i threw another one in there. This one survived long enough for me to DX the issue.

They all worked with the lights off, with the lights on the drivers front didnt work and the flasher ran very slow. I had read another thread on blinkers on the forum here, and they had mentioned ground issue would slow the flasher down due to increased resistance so I thought this must be where the ground issue is. I took the replacement harness out I had wired up previously, and decided the wires were backwards even though this went against the wiring chart. I ended up wiring the blue/brown wire to the ground and the brown wire to the light, leaving the white/blue wire wired to the light.

That resolved the slow flasher and got the front blinker blinking while the parking lights and/or headlights were on.

I went ahead and fiddled with the guage panel and also got the right blicker indicator working by swapping around the bulbs.

I should have caught all this sooner but a series of errors on my part some how kept me missing the obvious

Thanks again for your help!

 

Very good exchange of info in this thread and I appreciate the play by play on how you resolved it pondbear, often folks get advice and then you never hear how things wound up.

 

Good posts .... I still have to track down why my drivers side signal wont work with the headlights on ... I've cleaned the grounds from the sockets, but Think i'll try switching out the bulb sockets ..... Then onto the f@#%@#% ing cruise system .....

 

trap4x4 - I had originally tried the "coca-cola" trick on the sockets, thinking they were corroded and figuring the coca-cola would eat off some of that corrosion. Through this process I learned that those rubber gasket/washer/things that meet the bulb holder and protect the wire were pretty air tight so I ended up pulling on them with pliers to get the coke to "flow" through the assembly.

Ultimately, I decided to just replace both of the front parking light assembly's with new ones. They had them at advance auto (for 9.99 a piece) .. When I was finally able to get everything working _with_ the parking lights and headlights on EXCEPT the front driver side blinker, thats when I started evaluating my wiring. There was what I think was a ground running up to the metal above and in front of the radiator (dont know what you call this) so I unscrewed it, scraped off all the paint, covered it with dielectric grease, and screwed it back in, that way my assumption was now there was no way my ground could be bad, but still no dice.

Then I just took a gamble with swapping the wires around even though the test light and the wiring diagram indicated I had wired it correctly. Switching the wires around ultimately fixed it.

This may sound like the dullards approach, but there are only 3 wires connected to the bulb assembly, so if you are down to just a single light issue, it may be worth wiring it every way possible to see if any combination (regardless of test light or wiring diagram advice) will resolve your issue.

thx for the kind words, this was a good thread and thanks to all who contributed to help a new mechanic like me!

 

Pretty much the same thing happened to me. Replaced the LF turn signal socket and wired it wrong. I wish the replacement sockets would have some form of tag on the wires to help us backwoods electricians know which wire should go where since the new wiring is nothing like the old.

 

Great point, I find this frustrating as well. The two filaments in an 1157 bulb have different resistance, so swapping the wiring will adversely affect the turn signal circuit (which depends on resistance to function properly).

Glad to hear you got it worked out - don't forget to put the regular fuse back in

 

I don't want to hijack this thread but I have some of the old fuses in my truck and have been wondering how to replace them when the time comes. Are old ford fuses with brown, light blue, yellow stripes comparable to AGC and AGW fuses? Can you still purchase fuses with the color stripes?