Terrano air con probs
 

hello
help needed with air con. The light on the dash is dimly liton the switch but the compressor does not run until you put direct power to it from the battery then it blows cold.
Had the car to nissan dealer for two days and they said they were not sure what the problem waseven though it had been on there computer but said it was an electrical fault .
Any help would be appreciated
Thanks