Why does the blinker blink fast? [Solved] 2000 Chevrolet S-10
Affiliate Disclosure: As an Amazon Associate, we may earn commissions from qualifying purchases from Amazon.com.
Here is a list of tools I use every day at the shop. Let me know if you use them too in the comments!
Customer Complaint:
This 2000 Chevrolet S-10 came to the shop with a complaint of the right turn signal flashing too fast.
First Thoughts:
There are several different reasons a why a blinker may be blinking fast.
Here are some common issues for a fast blinker.
A bad bulb.
A broken wire.
Another wiring issue like a severe corrosion
Diagnostics:
This particular truck has been very difficult for the customer. Several mechanics have looked at it and could not figure it out. Several new bulbs have been installed and the problem still remains.
Since multiple new bulbs were installed, I have a strong feeling that a bad bulb is not the problem. Although, I always keep the idea of bad “new” parts in my head when diagnosing a vehicle.
There is one clue that the truck is giving me that will help in the diagnostic process.
When the right side blinker is on, multiple bulbs flash with it, but very dimly.
In most cases, this is an indication of a bad ground.
I pulled out my Power Probe IV, and started to check the ground of the blinker circuit.
If you do not have a Power Probe, I would consider buying one. It would be a giant improvement when diagnosing electrical issues on any vehicle. I use my Power Probe IV daily to check everything from alternators to powers and grounds on different components.
Back-probing the ground wire on the turn signal with it off - Looks like a good ground, but is not when loaded
Back-probing the ground wire on the turn signal with it on - loaded circuit reveals a bad ground
When back probing the grounds on a circuit, the system has to be “loaded” to show a problem.
Loaded means the component that the circuit controls has to be on.
The picture with the 00.02 volts is when the blinker is off on this truck. If I were to say “the ground is good"“, I would have been completely wrong.
The picture with the 6.17 volts is the ground when the turn signal is on.
It is suppose to have near zero volts on it when the blinker is on, but it does not.
I have found my problem! The blinker is missing a good ground.
After diving into a wiring diagram, I found the ground on this vehicle. It is below the right rear tail light, underneath the truck.
Corroded ground wire that broken when I touched it.
The ground for this truck goes from a single wire on the frame to a junction that splits into multiple wires.
The picture above is of the junction and the top of the picture shows a broken ground wire.
When I tugged slightly on the ground wire going to the frame, it snapped, revealing an enormous amount of corrosion on the wire.
After replacing the wire, the blinker works properly. Fixed!
Disclaimer and Disclosure:
Due to factors beyond the control of DiagnosticMechanic.com, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. DiagnosticMechanic.com assumes no liability for property damage or injury incurred as a result of any of the information contained in this website. DiagnosticMechanic.com recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this website. Due to factors beyond the control of DiagnosticMechanic.com, no information contained in this website shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this website is the sole responsibility of the user and not DiagnosticMechanic.com.
DiagnosticMechanic.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. In many of our case studies, articles, and tool reviews, we may earn a small commission when readers purchase products through our links.