Skip the auto shop - Our mechanics make house calls

Q: My Tach doesn't read correctly sometimes. Power locks and wiper blades don't work all the time.

asked by on

Start the truck up and the tach will read 500 rpm most of the time when cruising (Truck sounds just fine). Power Locks on the doors, and the wiper blades dont work all the time. Sometimes when they dont work, I will turn the truck off then on then they work just fine.

My car has 130000 miles.
My car has an automatic transmission.

A: The problem with your tach sounds like it m...

The problem with your tach sounds like it may be within the mechanical workings of the tachometer itself. If the gears that moves the needle around start to wear, you may have a bouncing needle or it can stop in one place. While the vehicle is hooked to a scan tool, you can watch the engine rpm on the scanner and if that reads 500 rpm as well as on the dash and the engine is definitely spinning faster, the sensor may be at fault. The power door locks and wiper problem may be separate problems as they don't share many circuits. A loose ground connection can cause this type of problem as well as failing command switches or the relays that control these components. Consider hiring an experienced technician like one from YourMechanic who can come by for a closer look at the faulted electrical circuits to see where this bug is.

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: Can build pressure in front brakes

In order to properly bleed the ABS brakes on this vehicle you will need to have a scanner that can put the ABS into bleed mode. This will open the valves in the ABS brake modulator so you can bleed...

Q: Do I have a problem with the electrical system?

Hi, thanks for writing in. The charging system is not very complicated. If the alternator and the battery are absolutely 100% good, no doubts about it, then the issue is likely a bad ground. Both the battery and the alternator...

Q: Need help with block heater cord on my van

Hello. From the factory, the block heater comes out of the front of the vehicle. Depending on if you are using the factory system or if you are using an aftermarket unit you may need to mount it someplace else...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...