Turn signals don't blink when headlights are on

[Morty]

My turn signals do not blink when the headlights are on. The voltage drop is about 4 volts with headlights on and 2 volts when the park lights are on. The negative voltage meter ground test registers about 4 volts at three grounds when it should be 0.03 or so. Also the positive wire test indicates the voltage is down to about 9 volts. The culprit is likely a corroded wire or connector somewhere. But I don't know how to find the problem.
What’s been done?
•Replaced turn signal flasher and all bulbs. I also cleaned the sockets.
•Tested fuses.
•Cleaned all the grounds I could find .i.e. the three in the front. The rear ones look okay.

Welcome advice on next steps?

[Lumpy]

My turn signals do not blink when the headlights are on. The voltage drop is about 4 volts with headlights on and 2 volts when the park lights are on...

Elaborate, please. Are you saying -

Engine off, volt meter in PARALLEL with the battery you see those voltage drop figures? or something else?


Lump

[Morty]

When the headlights are on the voltage drop is 4 Volts . When turn signals are used with motor running and the headlights are on the signals do not blink. They do blink when the headlights are not on.

[Lumpy]

It's broke.

Without a more elaborate description of how you're measuring that voltage drop, I, at least, am unable to help.

Please describe how, and with what instrument(s) and where in the system you're measuring this voltage drop.

What's your battery voltage with engine off?

What's your alt output voltage with accessories off, engine running?

Run the van for 5 minutes. Shut engine off. Turn on headlamps for 1 minute then shut headlamps OFF. Measure the battery voltage then, engine off, key off, accessories off.

What's your parasitic draw current?

What is "The negative voltage meter ground test"?

You measuring with a DVM? Replace the battery in the DVM.

You like Nachos and beer?


Lump

[RECox286]

I don't off-hand know how many volts it takes to fire the flasher unit, but if you are down to

9vdc with the headlamps on and the engine off, I would suggest that you have the battery

load tested.

Static (no load) battery voltage at the battery terminals should register 12 to

13 volts. That is 2.2vdc per cell x 6 cells = just over 13vdc for a brand new battery.

(Consider how old the battery is, as they do degrade with age as the materials inside

break down.)


When you start the engine with a VOM checking voltage at the

battery terminals, how much does the starter drag down the voltage reading. If it drags

the voltage below 10vdc, it may indicate (usually) that the battery has an internal problem

and should be replaced. (It could indicate other problems as well.)


Next, with the engine running and the VOM still at the battery terminals, what is the meter

reading ? Alternator output voltage should show 14 to 15 vdc.



If you are not sure about doing this, most LAPS offer free testing and diagnosis as it helps to sell parts.

Good hunting

Uncle Bob

[Lumpy]

...Consider how old the battery is, as they do degrade with age as the materials inside break down...

Just like my joints...


Lump

[Morty]

I am using a Innova 3300 Voltage Meter. It is working as I get 12.8 volts from positive to negative battery terminals. With the headlights on, the voltage from the battery negative to all three grounds in the front read 3.4 volts. This should be about 0.03 no? When just the park lights are on the voltage reads 2.11. With the motor running and the curtsey light on the meter reads 1.1.

[Lumpy]

In troubleshooting electrical, perhaps more than any other system, attention to detail in discovering and defining symptoms is vital. It doesn't appear you have married into that concept yet.

Your van's broke.


Lump

[Morty]

Let me restate the electrical issue with my 1986 van. I am experiencing a voltage drop. I likely have a corroded wire or connector somewhere but I don't know how to pin-point the problem? I replaced the turn-signal flasher and all bulbs. I also cleaned the bulb sockets. I tested the fuses. I cleaned the grounds. Welcome any advice on what else to do or how to identify a corroded wire or connector ?

[Morty]

[Perseverance is the investment; Success is the Return ]. Let me restate the electrical issue with my 1986 van. I am experiencing a voltage drop. When the headlights are on, the turn-signals, with motor on, will glow but do not blink. I suspect a corroded wire or connector somewhere but I don't know how to pin-point the problem? I replaced the turn-signal flasher and all bulbs. I also cleaned the bulb sockets. I tested all the fuses. I cleaned the grounds. Welcome any advice on what else to do or how to identify a corroded wire or connector? Can anyone offer specific advice other than the van is broke. I'll also check elsewhere.

[chevymaher]

Check the common ground on the radiator core support. Follow the small battery wire it bolts on there.
Behind the battery on the firewall there is a common hot supply plug it likes to melt.

[Lumpy]

...Can anyone offer specific advice other than the van is broke.

You've been offered several diagnostics and questions. None of which you've answered or commented on. All I keep hearing you say is "I've got a voltage drop".

Answer the questions specifically. Do the diagnostic steps suggested. Double posting the same thing you've already posted twice before clearly isn't getting you any results.

Until you give a little more information the only answer anyone can come up with is, your van is broke.

You want guesses? I'll guess you've got one or more bad grounds, bad battery, bad wiring, bad alternator, bad lamp sockets or bad light switches.

Maybe if you post the same question just two times more someone will magically hit on the answer you want to hear.




Lump

[Morty]

Hmmm ... I am new to a forum and new to solving electrical issues. I'll go back to the previous posts and try the suggestions. The battery however should be good if it reads 12.8 volts on a voltage meter ... correct??

[chevymaher]

yes

[Morty]

Here are responses to previous posts
Please describe how, and with what instrument(s) and where in the system you're measuring this voltage drop. Using a voltage meter. Measured from the negative battery terminal to the RH Front and LH front grounds attached to the fenders. This reads 3.8 volts with the headlights on. it reads 2.11 with just the park lights on

What's your battery voltage with engine off? 12.8 volts

What's your alt output voltage with accessories off, engine running? 14.47

Run the van for 5 minutes. Shut engine off. Turn on headlamps for 1 minute then shut headlamps OFF. Measure the battery voltage then, engine off, key off, accessories off. 12.66

What's your parasitic draw current?
With the engine running and the VOM still at the battery terminals, what is the meter
reading ? TBD Alternator output voltage should show 14 to 15 vdc.
Check the common ground on the radiator core support. Follow the small battery wire it bolts on there.
Behind the battery on the firewall there is a common hot supply plug it likes to melt TBD
Work done: Tested fuses, cleaned grounds and replaced

[chevymaher]

Okay battery and charging system are working fine. For whatever reason there just isn't any voltage/amperage getting to the light circuit. Was the power feed behind the battery okay. Unplug it and it was or wasn't burnt in the plug. With the battery staying properly charged I leaning to a power feed to the interior being bad.

[Lumpy]

I don't know what the heck's going on with that 3.8v from negative terminal battery to ground. There should be essentially zero voltage there unless there's a bad ground cable.

You've got a bad ground somewhere. I'd suspect it's at the battery terminal or in the battery to ground cable/wire/connection.

If you have ONE cable going from NEG battery to ground, remove that cable and measure it's resistance. If it's essentially zero, suspect the connections on either end, battery and engine/frame whatever it's connected to.

Do the same for the positive side. If your van is stock, you've got one big cable going from positive battery to the starter. Then smaller wire(s) from there feed the rest of the van. See if your starter connections are secure. Clean them, apply dialectric grease etc.

Suspect the smaller wires that lead from that starter, through a fusible link, to the alternator, then to the rest of the van. That typically means the connection through the firewall that Chevymaher is talking about. It's behind the battery on the firewall.

Don't assume the problem is limited to your lights. They're just the highest current draw devices, 2nd only to the starter. If the starter seems to be spinning fast and normally, suspect the wiring AFTER the starter to the alternator, the firewall connector etc.

Low voltage, high current systems (automobiles) are very sensitive to resistance. Example - a 10A load (typical pair of sealed beam headlamps) is about 1.3 ohms of resistance (only!), figured at 13v. That means that if your system has just ONE additional ohm of resistance somewhere, it will drop the voltage to the headlamps by nearly half. It's like putting 2 headlamps in SERIES. Tiny resistances in car circuits cause tremendous voltage drop and/or tremendous current draw. That's why the Big 3 upgrade causes such a dramatic improvement. You're wringing out every last thousandth of an ohm and thereby allowing more voltage to flow to the intended devices.

I know you said you checked and cleaned grounds. Double check them. Install new and redundant grounds. Look for "horses not zebras" first. Take care of all the battery and up front wiring before suspecting things like the headlight switch. Do that primarily because it needs it anyway and might resolve the problem.

While you're testing, your horns are another high current demand accessory. See if you can measure voltage drop while the horns are honking. That may help you expand the search from the headlights and turn signals to something more all encompassing, like the battery and it's cables.

Thanks for the more detailed info.


Lump

[RECox286]

you should look in the area behind the battery (remove the battery) where there are a whole bunch of

wires, most of which are concealed in plastic conduit(s). Strip the conduit away from the wires, and

inspect each wire for "puffy"or a "discoloration" of the insulation. That is what happens when corrosion,

due to battery acid, blooms within a copper wire sheathed by insulation. Corrosion will increase the

resistance value of the wire in question, until the wire no longer can perform its' function. This is a

quite common problem with automotive wiring that is close to a battery that leaks electrolite, even

just a little bit, and I've never seen a wet cell battery that didn't ooze some liquid. I have had several

insidents requiring cutting out and replacing sections of corroded wiring, that were located in back of

the vehicles' battery, when the wires finally failed to carry any current at all. NOTE: You may have to

"stab" some wire insulation to be able to properly inspect them with your meter probes.

Good hunting

Uncle Bob

[Morty]

Thanks for all the good advice. I'll get to it tomorrow as I am out on my boat today. I do have a confession to make. It's a 1986 Ford Econoline Campervan. I couldn't find a Ford Forum that I could get onto. Hope this was okay to sneak in with the Chevy guys.

[Lumpy]

One more thing you could try. If you have a set of jumper cables, connect one end of the black cable to the battery ground. Place your tongue on the positive terminal of the battery. Place the other end of the black cable up your asz. And be sure and post pics. We love pics.


Lump