LTD LX turn signals, back up lights not working

[zak]

Got the LTD LX reassembled (new water pump) and drove it for the first time in months yesterday. For some reason the turn signals won't work.

The 85 factory service manual doesn't seem to have much of a diagnostic routine. I did find out the back up lights are on the same circuit, and verified that they are not functioning.

Pulled the fuse and checked it with a resistance meter and its good.

Any ideas appreciated - I did have the center console apart, and the drivers dash apart recently.

zak

[zak]

Got the LTD LX reassembled (new water pump) and drove it for the first time in months yesterday. For some reason the turn signals won't work.

The 85 factory service manual doesn't seem to have much of a diagnostic routine. I did find out the back up lights are on the same circuit, and verified that they are not functioning.

Pulled the fuse and checked it with a resistance meter and its good.

Any ideas appreciated - I did have the center console apart, and the drivers dash apart recently.

zak

[79 Road Runner]

I had an issue with my 82 stang (a "few" years ago) and the brake lights suddenly quit. I spliced a wire that ran along the door to the taillights and checked for conductivity with a voltmeter. That helped narrow down where I had to start looking. I had a connector loose behind the kickpanel or dash (if I recall correctly)...

Of course the basic idea is to follow the circuit and check for conductivity where it should be and continuity where it should not be... If you work from end to end, you can trap the problem between two places and you can usually figure out the culprit: short or bad connection (e.g. dirty connectors/switch or loose connection).

I had a faulty turn signal switch that - once cleaned - worked properly thereafter. Considering the backup lamps aren't working, I'd guess they're not at fault. You can probably use your wiring diagram to help you narrow down your search.

Hope that helps...

[79 Road Runner]

I had an issue with my 82 stang (a "few" years ago) and the brake lights suddenly quit. I spliced a wire that ran along the door to the taillights and checked for conductivity with a voltmeter. That helped narrow down where I had to start looking. I had a connector loose behind the kickpanel or dash (if I recall correctly)...

Of course the basic idea is to follow the circuit and check for conductivity where it should be and continuity where it should not be... If you work from end to end, you can trap the problem between two places and you can usually figure out the culprit: short or bad connection (e.g. dirty connectors/switch or loose connection).

I had a faulty turn signal switch that - once cleaned - worked properly thereafter. Considering the backup lamps aren't working, I'd guess they're not at fault. You can probably use your wiring diagram to help you narrow down your search.

Hope that helps...

[paul78zephyr]

Yes the turn signals and the back-up lamps share the same fuse but you seemed to have ruled this out. Humor me. Does your heater and AC blower fan motors work?

Paul

[paul78zephyr]

Yes the turn signals and the back-up lamps share the same fuse but you seemed to have ruled this out. Humor me. Does your heater and AC blower fan motors work?

Paul

[pextor]

Yes the turn signals and the back-up lamps share the same fuse but you seemed to have ruled this out. Humor me. Does your heater and AC blower fan motors work?

Paul

that would be my question as well. that would point toward the ignition switch.

[pextor]

Yes the turn signals and the back-up lamps share the same fuse but you seemed to have ruled this out. Humor me. Does your heater and AC blower fan motors work?

Paul

that would be my question as well. that would point toward the ignition switch.

[paul78zephyr]

Darn it Pextor, you stole my punchline! Just kidding.

If there is a particular problem at the ignition switch with the one contact that carries power via circuit 687 (GRY/YEL) you will loose power to fuses F5 and F9. F5 is the turn signal and back-up lights. F9 is the heater and AC blowers.

As a test remove fuse F5, turn the ignition switch to on/run (the engine can be off) and using a VOM meter check for battery voltage between one fuse terminal and ground. Unless you remove the fuse box and turn it over it may be difficult to know exactly which side of the fuse is 'hot' - its the side with the GRY/YEL wire - so if you cannot remove the box just check both fuse terminals, it will do not harm. If no voltage there do the same at fuse F9. If no voltage there either your ignition switch has a dead terminal and will need to be replaced.

Paul

[paul78zephyr]

Darn it Pextor, you stole my punchline! Just kidding.

If there is a particular problem at the ignition switch with the one contact that carries power via circuit 687 (GRY/YEL) you will loose power to fuses F5 and F9. F5 is the turn signal and back-up lights. F9 is the heater and AC blowers.

As a test remove fuse F5, turn the ignition switch to on/run (the engine can be off) and using a VOM meter check for battery voltage between one fuse terminal and ground. Unless you remove the fuse box and turn it over it may be difficult to know exactly which side of the fuse is 'hot' - its the side with the GRY/YEL wire - so if you cannot remove the box just check both fuse terminals, it will do not harm. If no voltage there do the same at fuse F9. If no voltage there either your ignition switch has a dead terminal and will need to be replaced.

Paul

[twister]

the back-up lamps go through the nuetral safety switch, so if you get the turn signals working....

As for the turn signals, if one bulb is out on one side, that entire side is not going to work.

do the tail lamps work?

[twister]

the back-up lamps go through the nuetral safety switch, so if you get the turn signals working....

As for the turn signals, if one bulb is out on one side, that entire side is not going to work.

do the tail lamps work?

[zak]

Thanks everyone for the ideas. The heater blower definetely works.

The ignition switch was replaced about 5 years ago with an aftermarket one when Ford was hvaing the massive recalls for the same switch on newer models. Have not had the column apart since then.

I had thrown a new blinker relay at it to no effect, before realizing that the back up lights were out as well.

Should I still open up the column and explore this "F5" circuit? With KOEO, and the fuse pulled I get continuity with the blinker switch in a turn position, continuity goes away when the blinker switch is put in neutral (middle positon).

Appreciate the advice, and have a happy new year - zak

[zak]

Thanks everyone for the ideas. The heater blower definetely works.

The ignition switch was replaced about 5 years ago with an aftermarket one when Ford was hvaing the massive recalls for the same switch on newer models. Have not had the column apart since then.

I had thrown a new blinker relay at it to no effect, before realizing that the back up lights were out as well.

Should I still open up the column and explore this "F5" circuit? With KOEO, and the fuse pulled I get continuity with the blinker switch in a turn position, continuity goes away when the blinker switch is put in neutral (middle positon).

Appreciate the advice, and have a happy new year - zak

[paul78zephyr]

Are you checking for battery voltage? Connecting one side (supply side) of that F5 fuse and ground with a voltmeter should give battery voltage with the ignition switch in on/run. Verify this.

If you are connecting the load side of the fuse and ground and checking for continuity (resistance) then yes, you should have continuity with the turn signal switchn in either left or righ on position, and no continuity (open) with it in the off position.

If you have voltage and the correct continuity pattern (as you seem to) then you must have a bad fuse or connections to the fuse. Try checking by temporarily installing a jumper wire across F5s terminals and try with ignition switch on. Remember doing this removes any safety in the circuit so check it quickly.

[paul78zephyr]

Are you checking for battery voltage? Connecting one side (supply side) of that F5 fuse and ground with a voltmeter should give battery voltage with the ignition switch in on/run. Verify this.

If you are connecting the load side of the fuse and ground and checking for continuity (resistance) then yes, you should have continuity with the turn signal switchn in either left or righ on position, and no continuity (open) with it in the off position.

If you have voltage and the correct continuity pattern (as you seem to) then you must have a bad fuse or connections to the fuse. Try checking by temporarily installing a jumper wire across F5s terminals and try with ignition switch on. Remember doing this removes any safety in the circuit so check it quickly.

[zak]

Paul, thanks again for the advice, will check voltage in a bit. as it appears that my Fluke 10 will read voltages (doesn;t seem to respond to the Select and Range buttons though).

I took the car out on an erand the other evening, with cabin ambients at 30-35 F the turn signals worked (can't remember if the car had dash indicators for the turn signals, if present they were not working).

After the cabin warmed up, the turn signals stopped working.

Will check voltages today. One more recent upgrade was to swap to a circa 1996 small case 3G alternator.

- zak

[zak]

Paul, thanks again for the advice, will check voltage in a bit. as it appears that my Fluke 10 will read voltages (doesn;t seem to respond to the Select and Range buttons though).

I took the car out on an erand the other evening, with cabin ambients at 30-35 F the turn signals worked (can't remember if the car had dash indicators for the turn signals, if present they were not working).

After the cabin warmed up, the turn signals stopped working.

Will check voltages today. One more recent upgrade was to swap to a circa 1996 small case 3G alternator.

- zak

[paul78zephyr]

Im not sure about the temperature issue.

If you had said that only the turn signals (TS) were not working (or intermittent) and the backup (BU) lights were OK Id have pointed at the TS flasher which could be affected by temp. But if both the TS and BU circuits are dark then it must be either a problem with fuse F5 or the fuse's terminals. Your other test (continuity) verified that the rest of the TS circuit is OK. I am ruling out the the ignition sw and its GRY/YEL feed wire to fuses F5/F9 as you say the circuit on F9 (heater and AC blowers) are OK. You got to do that voltage test and if voltage is present then jumper across F5 (briefly) and try TSs and BUs.

Paul

[paul78zephyr]

Im not sure about the temperature issue.

If you had said that only the turn signals (TS) were not working (or intermittent) and the backup (BU) lights were OK Id have pointed at the TS flasher which could be affected by temp. But if both the TS and BU circuits are dark then it must be either a problem with fuse F5 or the fuse's terminals. Your other test (continuity) verified that the rest of the TS circuit is OK. I am ruling out the the ignition sw and its GRY/YEL feed wire to fuses F5/F9 as you say the circuit on F9 (heater and AC blowers) are OK. You got to do that voltage test and if voltage is present then jumper across F5 (briefly) and try TSs and BUs.

Paul

[zak]

Pextor & Paul, today the HVAC blower motor would not work with KOER.

With KOEO, and using the back of the radio as a ground, I verified power to a couple of circuits. However, both F5 and F9 were dead at the fuse box.

Given your suggestion, I tried wiggling the ignition lock with KOER, and lo and behold the turn signal, back up, and blower circuits all came on.

Maybe a Ford switch vs the "Parts Plus" switch thats in there now is the correct route (better replcaement)? I thought there was only one actual manufactuer, back when UTAuto and Ford were being investigaed by the NHTSA ahead of the recall for the 89 and newer switches of this type.

Hopefully the F5/F9 was not the circuit that was burning cars up. The F9 had a 30 amp fuse . . . .

Thanks again for your help - zak

[zak]

Pextor & Paul, today the HVAC blower motor would not work with KOER.

With KOEO, and using the back of the radio as a ground, I verified power to a couple of circuits. However, both F5 and F9 were dead at the fuse box.

Given your suggestion, I tried wiggling the ignition lock with KOER, and lo and behold the turn signal, back up, and blower circuits all came on.

Maybe a Ford switch vs the "Parts Plus" switch thats in there now is the correct route (better replcaement)? I thought there was only one actual manufactuer, back when UTAuto and Ford were being investigaed by the NHTSA ahead of the recall for the 89 and newer switches of this type.

Hopefully the F5/F9 was not the circuit that was burning cars up. The F9 had a 30 amp fuse . . . .

Thanks again for your help - zak

[LTDScott]

I had similar issues with my previous LTD. The ignition switch in the column was the culprit.

[LTDScott]

I had similar issues with my previous LTD. The ignition switch in the column was the culprit.