Taylor, 27, retired with a heart condition in April 2016 after seven England Tests and 27 one-day games.
He has since worked with Nottinghamshire and Yorkshire's academies in addition to media work.
"It's great to see his desire to still be involved with the game," head coach David Ripley said of Taylor's arrival.
"James has a fantastic 50-over record, averaging over 50 which is obviously outstanding.
"I believe he can offer good advice and relay his one-day cricket experiences on to our batsmen."
Meanwhile, former Northants captain Sales, who scored in excess of 22,000 runs in more than 20 years at the County Ground before his retirement in 2014, will work with the county's batsmen.
"David has been working part time with the batters since January, focusing on improving more of the technical aspects of their game," Ripley added.
"I believe his cricket brain and experience are a real positive for the squad and will go a long way to improving their overall game."

Transport for London (TfL) had wanted to provide £30m for the proposed £175m bridge set to stretch from Temple to the South Bank in Lambeth.
But talks broke down after Lambeth Council said not enough had been done to attract private sector backing.
Chair of the Garden Bridge Trust, Lord Mervyn Davies, said he was "delighted to move forward with the project".
In September, Lambeth Council halted negotiations and said it would only proceed if assurances were made that £30m was not taken from Transport for London.
Lambeth council leader Lib Peck said: "I'm pleased we've successfully agreed a deal that will cut London taxpayers' contribution towards the Garden Bridge by two thirds."
Plans for the bridge were approved in 2014, after Lambeth and Westminster City Councils granted planning permission with the chancellor and London Mayor Boris Johnson pledging £30m each, and the rest due to come from private funding.
Lord Davies said: "We have been hugely successful in our efforts to raise funds from the private sector, with £85m pledged to date, and we have agreed that any of the committed funds from TfL spent over the £10 million will be treated as a loan."
But Liberal Democrat Caroline Pidgeon from the London Assembly said: "While I welcome a reduction in Transport for London's payment towards the Garden Bridge, today's announcement simply raises more questions than it answers.
"Why did TfL ever agree in the first place to contribute £30m to the Garden Bridge?  How much will TfL be willing to lend the Garden Bridge Trust?"
The Trust said it hoped to begin working on the site in the New Year.
Former England batsman James Taylor has joined Northamptonshire as a coaching consultant, while David Sales has taken a part-time coaching role.
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Financial contributions to the Garden Bridge by London's public transport network have been limited to £10m.