Voltage drop with turn signals, hazards, or gas-pedal acceleration
October 13th, 2018, 6:08 PM
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Voltage drop with turn signals, hazards, or gas-pedal acceleration
Hi all!
I've had my 99 Suburban for almost 20 years. She's been a great SUV to me with the reliable 5.7 Vortec engine. But lately, I'm having an electrical problem that I cannot seem to solve.
Voltage drops from 14v down to 12v or less when turn signals applied. The blinkers flash really quick but not as intense or bright as it should be. All bulbs are functioning so no blown bulbs. At times, when turn signal is applied (left or right), the voltage will drop low enough to kill the engine while driving (any speed). The cluster also seems to shut off.
The voltage drop is also noted when the gas pedal is depressed; the more fuel demand, the lower the voltage drops, but this does not happen all of the time.
I have had my alternator and battery checked 3 times, and all 3 times it passed. I have checked the battery ground to engine, the engine to frame, and the frame to body grounds all checked good as well (ohms test). I also checked the rear-ground next to the fuel tank, and the ground behind the rear bumper. All appears well with the ohms testing.
Today I noticed that my ignition key gets hot when the voltage drops low enough, and you can feel the heat emitting from the ignition switch lock-cylinder. Could this be the problem? A faulty ignition switch?
As "number-five alive" would say, "INPUT! I NEED INPUT! MORE INPUT!"....."Short Circuit Movie"
Joe
I've had my 99 Suburban for almost 20 years. She's been a great SUV to me with the reliable 5.7 Vortec engine. But lately, I'm having an electrical problem that I cannot seem to solve.
Voltage drops from 14v down to 12v or less when turn signals applied. The blinkers flash really quick but not as intense or bright as it should be. All bulbs are functioning so no blown bulbs. At times, when turn signal is applied (left or right), the voltage will drop low enough to kill the engine while driving (any speed). The cluster also seems to shut off.
The voltage drop is also noted when the gas pedal is depressed; the more fuel demand, the lower the voltage drops, but this does not happen all of the time.
I have had my alternator and battery checked 3 times, and all 3 times it passed. I have checked the battery ground to engine, the engine to frame, and the frame to body grounds all checked good as well (ohms test). I also checked the rear-ground next to the fuel tank, and the ground behind the rear bumper. All appears well with the ohms testing.
Today I noticed that my ignition key gets hot when the voltage drops low enough, and you can feel the heat emitting from the ignition switch lock-cylinder. Could this be the problem? A faulty ignition switch?
As "number-five alive" would say, "INPUT! I NEED INPUT! MORE INPUT!"....."Short Circuit Movie"
Joe
Last edited by HorsingNaturally; October 13th, 2018 at 6:11 PM.
October 13th, 2018, 7:08 PM
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That was my original guess as well. So I removed the steering column covers and ran a voltage test on applicable turn signal wiring and they appeared to be fine; no ground-outs detected. I also checked amperage and voltage to both the right and turn signal. I did note a great deal of amperage when either the left or right turn signal is applied. But the switch lever itself never seems to get hot. The ignition key lock cylinder gets very hot, and thus the reason why I'm suspecting the ignition switch itself is bad and causing high amperage draw and heating up internally.
Also, I have noticed that the windshield wiper delay doesn't seem to work very well at times. With the longest delay setting, the wipers will wipe more frequently or with no delay at all. This would seem to suggest a failing turn signal switch lever.
With the hazard lights engaged, the voltage also drops, but not near as low as when the turn signals are applied. Shut down the vehicle but leave the key in the run position, and the turn signal works just fine without the fast blinking or severe voltage drop. But as soon as you start the engine, and apply the turn signals, the voltage drops dramatically and even sometimes kills the engine.
Tough one for sure. I suppose I should just go ahead and replace the turn signal lever since it is not too expensive; I found a few on Ebay for about $40 bucks.
Joe
Also, I have noticed that the windshield wiper delay doesn't seem to work very well at times. With the longest delay setting, the wipers will wipe more frequently or with no delay at all. This would seem to suggest a failing turn signal switch lever.
With the hazard lights engaged, the voltage also drops, but not near as low as when the turn signals are applied. Shut down the vehicle but leave the key in the run position, and the turn signal works just fine without the fast blinking or severe voltage drop. But as soon as you start the engine, and apply the turn signals, the voltage drops dramatically and even sometimes kills the engine.
Tough one for sure. I suppose I should just go ahead and replace the turn signal lever since it is not too expensive; I found a few on Ebay for about $40 bucks.
Joe
October 13th, 2018, 8:02 PM
#4
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That was my original guess as well. So I removed the steering column covers and ran a voltage test on applicable turn signal wiring and they appeared to be fine; no ground-outs detected. I also checked amperage and voltage to both the right and turn signal. I did note a great deal of amperage when either the left or right turn signal is applied. But the switch lever itself never seems to get hot. The ignition key lock cylinder gets very hot, and thus the reason why I'm suspecting the ignition switch itself is bad and causing high amperage draw and heating up internally.
Also, I have noticed that the windshield wiper delay doesn't seem to work very well at times. With the longest delay setting, the wipers will wipe more frequently or with no delay at all. This would seem to suggest a failing turn signal switch lever.
With the hazard lights engaged, the voltage also drops, but not near as low as when the turn signals are applied. Shut down the vehicle but leave the key in the run position, and the turn signal works just fine without the fast blinking or severe voltage drop. But as soon as you start the engine, and apply the turn signals, the voltage drops dramatically and even sometimes kills the engine.
Tough one for sure. I suppose I should just go ahead and replace the turn signal lever since it is not too expensive; I found a few on Ebay for about $40 bucks.
Joe
Also, I have noticed that the windshield wiper delay doesn't seem to work very well at times. With the longest delay setting, the wipers will wipe more frequently or with no delay at all. This would seem to suggest a failing turn signal switch lever.
With the hazard lights engaged, the voltage also drops, but not near as low as when the turn signals are applied. Shut down the vehicle but leave the key in the run position, and the turn signal works just fine without the fast blinking or severe voltage drop. But as soon as you start the engine, and apply the turn signals, the voltage drops dramatically and even sometimes kills the engine.
Tough one for sure. I suppose I should just go ahead and replace the turn signal lever since it is not too expensive; I found a few on Ebay for about $40 bucks.
Joe
October 13th, 2018, 9:51 PM
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Here is a video I made a few hours ago so everyone can see what's happening. However, since the weather and humidity is much lower during the making of this video, the voltage drop was not near as severe as it is under higher humidity and temperatures.
Joe
Joe
October 14th, 2018, 5:50 AM
#6
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A voltage drop does not always indicate a short. It may be a high resistance connection instead of a short. I'd suspect the ignition switch since the OP mentioned that it get hot when the voltage drop is occurring. It could be a loose connection at the switch. Look for burnt wires & connectors in the steering column wiring harness.
October 14th, 2018, 12:25 PM
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A voltage drop does not always indicate a short. It may be a high resistance connection instead of a short. I'd suspect the ignition switch since the OP mentioned that it get hot when the voltage drop is occurring. It could be a loose connection at the switch. Look for burnt wires & connectors in the steering column wiring harness.
Here is another short video of this morning's drive.
Joe
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October 15th, 2018, 3:06 PM
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GREAT NEWS! VOLTAGE DROP PROBLEM SOLVED!
The problem was definitely in the ignition switch. I purchased the new ignition switch this morning (PN: CS542) from Advanced Auto Parts (didn't have enough money to buy the AC Delco version), and the problem is now solved. Upon removing the switch, I noticed that the male end with the bolt on the old switch harness was not tight. This resulted in an intermediate connection and over the past few years (or less), the weak connection caused high amperage in the switch mechanism and melted/broke the spring. The base of the connector (part that bolts to the female connector under the dash) was black on some areas. Before installing the new switch, I checked for possible short-to-ground, and all checked good. After about an hour of work, the new switch was installed, and the Suburban now runs like a champ. My headlights are brighter than ever, the turn signals and brake lights function correctly, and the hazard lights were correctly, and all without any voltage drop; she remains at 14 volts no matter what I turn on.
So PROBLEM SOLVED! Weak/Intermittent ignition switch and harness.
Thanks for all of your inputs guys!
Joe
The problem was definitely in the ignition switch. I purchased the new ignition switch this morning (PN: CS542) from Advanced Auto Parts (didn't have enough money to buy the AC Delco version), and the problem is now solved. Upon removing the switch, I noticed that the male end with the bolt on the old switch harness was not tight. This resulted in an intermediate connection and over the past few years (or less), the weak connection caused high amperage in the switch mechanism and melted/broke the spring. The base of the connector (part that bolts to the female connector under the dash) was black on some areas. Before installing the new switch, I checked for possible short-to-ground, and all checked good. After about an hour of work, the new switch was installed, and the Suburban now runs like a champ. My headlights are brighter than ever, the turn signals and brake lights function correctly, and the hazard lights were correctly, and all without any voltage drop; she remains at 14 volts no matter what I turn on.
So PROBLEM SOLVED! Weak/Intermittent ignition switch and harness.
Thanks for all of your inputs guys!
Joe