Skip the auto shop - Our mechanics make house calls

Q: Brake ABS CEL on/off . ABS pulses once during braking, electrical system goes weak, wiper and lights weak.

asked by on

When the truck starts, CEL for ABS and Brake light fluctuate on/off. Driving and when I brake, the ABS pulses once , can feel it in my foot. Headlights go dim, wipers run like they don't have much juice. At times, I have turned engine off with key out but engine continues running, put key back in, turn it on, wait for ABS/Brake CEL to go off then I can stop the engine.

My car has 141000 miles.
My car has an automatic transmission.

A: I don't know if all this started happen...

I don't know if all this started happening simultaneously or if these issues have been slowly accumulating, but here is how I would proceed: begin with a battery test and clean and make sure to tighten the cable connections. Replace the battery if needed before continuing.

Next, test the alternator output and be sure to check for A/C voltage ripple from the alternator. Belt must be good and at the correct tension. There have been faulty brake fluid level switches found. There have been issues with both the instrument cluster and ABS system on these trucks. They must communicate with each other, and can be tested with a scan tool to gather any existing diagnostic trouble codes (DTCs) to assist with diagnosis. Check for codes and module communication on the network.

If you want to have this done, a technician from YourMechanic can come and diagnose the warning lights and any of the other symptoms your car is exhibiting so that correct repairs can be made.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Lighting

This is most likely a bad headlight switch. When you pull the knob, there is a switch that makes contact which completes a circuit and turns your headlights on. When this switch goes bad, this can happen. This can also...

Q: What precautions should be followed with the supplemental restraint system?

Your car is equipped with a supplemental restraint system (SRS) – your air bags. There are several air bags throughout the cabin, but it’s important that you follow some safety precautions here. While air bags can help to keep you...

Q: Is slightly excessive lifting engine noise a problem? What is the best fix for it?

Hello. Slightly excessive noise, of any kind, from the engine may be an indication of accelerated wear to the engine. Keep in mind, however, that all engines operate differently, and some will generate more noise in their normal operation than...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.