Fast T's Mobile Alternator Testing

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​How Do you test an alternator?

Alternator testing basics
How to Test Alternator Voltag

Also see how an alternator operates HERE
A Quick lesson on Alternator Testing
by
Fast T's On Site Automotive Repair

An Introductory Lesson on Alternator Testing. Alternators are nothing more than a generator pulley driven by a belt. When the engine is running, on most cars the alternator will have an output to the battery positive of 13.4 volts to 14.7 volts. It may fluctuate depending on the vehicle, but as a general rule if it is putting out between 13.4 volts -14.7 volts to the battery + under a full electrical load with the motor idling, then the alternator is generating the correct level of voltage sufficient to power the vehicle and charge the battery.
A bad alternator is usually noticeably lower below 13 volts or above 15 volts which can damage electrical components, but most faulty alternators we come across are barely pushing 12 volts to the battery feed, and intermittent problems are rare.

SIMPLY SET YOUR MULTIMETER ON VOLTAGE TESTING, THEN TOUCH THE RED PROBE TO THE BATTERY POSITIVE, TOUCH THE BLACK PROBE TO THE NEGATIVE SIDE OF THE BATTERY….PRESTO!
WITH VEHICLE NOT RUNNING A GOOD BATTERY SHOULD HAVE 12.6 VOLTS, AFTER STARTING THE ENGINE THE MULTIMETER SHOULD READ ABOVE 13.4 VOLTS IF THE ALTERNATOR IS GOOD. 🤗

Basic testing is simple, although on rare occasions we need to graph the alternator for an identified intermittent charging or wiring problem, and many alternators these days require a little programming with the tablet to reset certain parameters on certain types of vehicles.

After confirming the fuses, or high amperage battery and alternator fuses are not blown, and making sure all electrical connections are solid, tight, and clean with ohms at 0 in between all circuits then alternator replacement may now commence following recommended procedures.
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**WARNING** NOT FOLLOWING PROCEDURES PROPERLY MAY HURT YOU OR YOUR CARS ELECTRICAL COMPONENTS. ALWAYS REMOVE NEGATIVE CLAMP COMPLETELY FROM POST ON NEGATIVE GROUNDED VEHICLES FIRST BEFORE WORKING WITH ELECTRICAL COMPONENTS. ON POSITIVE GROUNDED VEHICLES REMOVE THE BATTERY POSITIVE WIRE, IF YOU DO NOT KNOW, DO NOT ATTEMPT THE REPAIR.

A BAD ALTERNATOR WITH LOW VOLTAGE OUTPUT WHILE ENGINE RUNNING is below 13.4 volts

Good Alternator with output near 13.4-14.7 volts

Diagnose Your Alternator Problem & REPAIR IT!

CLICK NUMBER TO CALL NOW!1(515)318-1395

7 easy steps to change an alternator by Fast T

How to change an alternator simplified by Fast T's Automotive in Waukee Iowa.

Step 1: Remove negative battery terminal from battery and isolate or cover with rag so it can not touch or make a connection to the battery.

Step 2: Remove serpentine belt or alternator belt.

Step 3: Remove battery + wire from alternator by removing the nut.

Step 4: Unplug the alternator connector by pressing or lifting the tab.

Step 5: Remove the alternator mounting bolts.

Step 6 : Remove the alternator from engine.

Step 7: Reverse the 6 step process to install.

RETEST TO VERIFY FIX!!

With Fast T's Expedited Alternator Diagnostic & Replacement Service-
You Will Be Back On The Road In No Time, At An Affordable Price! Fast T's Charging Systems Diagnostic & Repair Experts, Are Always Available To Quickly Arrive At Your Location Anywhere In The Entire Des Moines Iowa Metro Area.
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"Put Your Mind At Ease " & Have
Fast T's Alternator Diagnostic & Replacement Service Repair Your Car Or Truck. We Have Been Changing Alternators On Engines For Over 30 Years!

Fast T's Expedited Mobile Repair Service, Is Your Local Car & Truck Alternator Professionals! Serving Waukee, West Des Moines, Iowa and The Entire Des Moines Metro Area and Suburbs Including Waukee, Clive, Johnston, Grimes, Windsor Heights, Urbandale, Adel, Booneville, Norwalk, Martensdale, Beaverdale, Windsor Heights, Ankeny, Altoona, Pleasant Hill, Carlisle and More In Central Iowa.