Very dim headlights

i have recently purchased a Santa fe 2006 model and the head lights are very dim I have been backwards and forwards to the salesman and he did suggest I use the fog lights to improve it but this isn't right. I would like to know if this is a common problem ? they are having the car back again on Saturday to take it to the MOT Testing station but I think that won't show the true problem. The lights hardly light up any distance from the front of the car when its dark, so I have a car that I can only use during daylight hour and this time of year are very few...

 

Can you measure the voltage at the bulb socket?
If less than 12 then you have a wiring problem (probably corrosion)
If okay then try replacing bulbs

 

Try replacing the bulbs as mentioned and update us. Thanks.

 

It is almost a month later and no update.
I think it is either resolved or the car was sold ... lol