2005-2011 Mercury Grand Marquis 250 to 400amp Alternator
Regular price $449.00 Sale price$349.00 Save $100.00
Have you been having Power issues?
Dim headlights? Low voltage? Bad sounding audio?
Are you tired of your vehicle's electrical system struggling to meet your demands?
Upgrade to a high-output alternator to ensure a steady and reliable power supply, even under heavy loads.
Shout out to JS alternators there the only ones who made a high output for my model car. Without it there’s no way I could run my current system on my stock alternator.
I highly recommend JS Alternators The craftsmanship is beautiful and they have great customer service everyone is so friendly and helpful. Fast shipping too. Satisfied customer for life!!!
JS alternators got me taken care of with Dual 400 amp illusion violent alts and I'm in love the customer service and quality is amazing..
Received two Alternators from JS and don't regret one moment of it. They have been great and when playing my system as hard as I can the Alternators have been able to keep up with all the power needed!
Orders ship in approximately 5-15 business days, sometimes sooner. If for some reason parts are on back order, we will notify you, but this is not common. If payments are being made on an order, your order will start processing when the order is placed.
We offer lifetime warranty on alternator labor and a one year warranty on parts. All orders are heavily wrapped for shipping with several layers of big bubble wrap and two layers of boxes along with a Fragile sticker on the box. If you have to ship your alternator back, please be sure you wrap it the same way to prevent further damage. See more details on our warranty page.
Each of our high output alternators come with smaller overdrive pulley. This pulley is made to increase low RPM charging for maximum output. It is custom for the diameter of the overdrive to be less than your factor pulley, depending on the kind of vehicle you own. For this reason, unless otherwise specified, you will need at least a 1/2 inch shorter belt. You can purchase this from any auto parts store. In using the belt and the pulley system, ensure that each part of the pulley system is free of oil or grease, this will help its efficiency.
It is important to make sure that the small regulator plug that is located on the back of the alternator is well plugged in for the correct functionality. Do not forget to plug it in completely, try not to jam the plugs in backwards, and avoid pinching it in order not to create a short. For more information on regulators and wiring see installation instructions.
Our high output alternators come with an overdrive pulley. The pulley is designed to improve low RPM charging so that it yields maximally. Do not change this overdrive pulley out with a larger diameter pulley. When alternator pulley diameter is increased, the output amperage decreases. Changing the pulley will void all warranties
As promised to all our customers, our products are fully tested ensuring their outstanding performance before shipping. In our experience through the years, it is in many cases not the alternator itself. You must ensure you consider a few possible concerns in your troubleshooting – please read the instruction manual thoroughly.
The reason could be one of two things: Either the plug is wired incorrectly or the computer is sensing the higher voltage and causing the battery light to come on even though the alternator is charging properly. Please refer to the instruction manual tab on the website for specific instructions that will help you with wiring. For some older vehicles, the factory style regulator is not available with the hairpin style alternator. This is why your high output alternator will come already “upgraded” with the 15 volt regulator. It will have an oval plug which requires splicing into the factory plug. This is a simple ,fast step and these instructions are detailed for you in the instruction manual.
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