Land Rover Repair: 95 RR Classic electrical issue..., control fan, time william

Question
I have a 1995 Range Rover County Classic with an intermittent electrical problem.  I recently had my heater core replaced while out of state and ever since then I have noticed that my tach will occasionally drop to zero, all of my lights will dim and the climate control fan will slow down.  I checked in my repair manual for a place to start looking.  I don't know where to start or what could be causing the problem.  I'm hoping that it is just an open caused by a poor connection.  

Please advise.

Thank you for your time,

William  

Answer
The symptoms you describe suggest there is an intermittent heavy drain - a short circuit - pulling down the voltage in your electrical system.  Thei could be a fault within your alternator, or it could be in the dash or elsewhere.

There is no way I could know if it's related to the heater core repairs.