The origin of this claim is Andrew Walden's 2010 article Wind Energy's Ghosts.
He is specifically referring to the wind turbines installed in California between 1981 and 1986 in three locations: Altamont, Tehachapi, and San Gorgonio. The article says 15,000 wind turbines were installed there in this time period.
An American Wind Energy Association report Repowering California Wind Power Plants, May 1993 confirms that by 1991 there were 16,873 wind turbines in Californina:
TEHACHAPI 5,259
ALTAMONT 6,835
SAN GORGONIO 4,012
SOLANO 600
PACHECO 167
(The wind industry uses the term "repowering" for decommissioning existing turbines and constructing new ones within the same wind farm. The 1993 reference is a plan to decommission 15587 of the 16,873 turbines)
So what is the current condition of these original wind turbines?
Already by 21 June 1999 there was a LA Times article Wind Farms Enter a New Generation:
The new windmills are slowly replacing ones less than half as tall that over the last 15 years have rooted like so many row crops along Interstate 10, just east of the San Gorgonio Pass.
The transition to the new wind turbines, which measure 296 feet tall from the ground to the tip of a rotor blade, is prompted by the 1996 deregulation of the state's electricity industry, which has forced wind farms to become more efficient. The $500,000 machines, with their 75-foot-long, 12,000-pound blades, spin more slowly but turn larger generators, creating about 15 times more electricity than their earliest predecessors.
Because their size requires more elbow room, fewer of the taller windmills are being erected to replace the smaller ones. At their peak in the late 1980s, nearly 4,000 wind turbines, 80 to 125 feet tall, dotted the area; eventually, the number will be reduced to the hundreds, operators predict.
So already by 1999 the 4000 at San Gorgonio Pass were being replaced.
A much more recent article, referring to Altamont pass, California Wind Farms Swap Out Turbines To Save Birds, says
They have applied for a permit to replace all of their obsolete equipment for newer state-of-the-art wind turbines that will be much less of a danger to birds. They notified the U.S. Fish & Wildlife service in October that they will be shutting down operations of all their older turbines over the winter.
Concerning the final location, Tehachapi Pass, Wikipedia says:
The first set of wind turbines installed were of American made Storm Master brand, however they failed.
Also, Tehachapi Renewable Transmission Project vol. 3 says:
During the late 1990s, wind power plant owners started repowering their existing turbines by removing the older turbines and replacing them with newer models.
So Andrew Walden's claim that 14,000 turbines have been abandoned is essentially true, the 15,000 wind turbines from the early to mid 1980s have been or are being replaced, with a much small number of much larger capacity turbines.
The other link in the OP, labeled "a number of fact-checking blogs" links to an American Wind Energy Association website, it is not a general fact check blog. It seems to be looking at the number of permanently inoperative wind turbines still in place.
The version in the OP (unlike Andrew Walden's original article) is saying that the 14,000 are left to litter the landscape (as opposed to being removed). This part isn't true. For example there is a 1997 article discussing removal costs of turbines and towers in San Gorgonio.
However, it seems that it was more true in 1989, as Western Tanger July-August 1989 states:
Les Reid, former National Director of the Sierra Club, criticized the DEIR for ignoring the issue of wind farm abandonment. "The abandoned wind farms in Tehachapi, San Gorgonio and Altamont demonstrate that the claimed benefits of wind farms are often illusory," said Reid. "Travelers passing through wind farm areas are confronted with rusting and lifeless wind machines, and the governmental agencies which granted the permits for the projects have had difficulty forcing the wind developers to remove this blight on the landscape," Reid stated.
Further confirmation that the 14,000 turbines were never simultaneous abandoned yet still standing is given by a 2012 interview with Paul Gipe:
In the late 1980s there were as many as 3,000 of the 14,000 wind turbines installed in California that were in various states of disrepair. For the most part, there were no laws or regulations that specifically required the operators to remove these turbines. They became eyesores. These junk turbines as I called them joined the burned out hulks of abandoned automobiles, the discarded sofas, trash and urban detritus that littered the peri-urban fringe where most of these turbines were located.
Fortunately, over the years nearly all those turbines have been removed and of the 11,000 wind turbines in California today only some 500 remain derelict.
Overall, the truth is the 14,000 1980s California wind turbines have been decommissioned. In the late 1980s there was a problem of dysfunctional wind turbines just standing there, at the worst 3,000 simultaneously. But by 2012 there were only about 500 in such condition.
