I recently replaced the alternator in my car due to a faulty voltage regulator in the old one. Since I had to wait for the alternator to come in, I decided to replace the hoses going to the radiator as well as the thermostat. This way I'm not worried about getting coolant all over the alternator. I installed the new alternator and everything works great. But now my wipers will turn on by themselves when the automatic headlights turn on. Also the passenger side headlight will not turn on. I thought I might have accidently poured coolant over the headlight connections, but everything was dry. Is there any easy fix for this? All the fuses are intact and I checked all the connections for a loose wire and couldn't find one. There is no check engine light on, so I'm at a loss for what it could be. Any suggestions are welcome.

 

It really helps to always post the year miles and model trim of your Mazda when asking for service related help

 

2006 mazda 3 s

 

So today I removed the passenger headlight and tested it by just connecting the headlight to the battery. So it works. Now the question is are there any loose wiring. Didn't find any. So the headlight relay (next possible problem) is part of the interior fusebox, So to replace it, you have to change out the whole fusebox assembly. I found several on ebay, but I would like to know that it is the problem as opposed to something else. The wipers only turn on by themselves if you put the light switch into the on or automatic setting. I'm realy thinking of giving up on this car, and moving on to something a bit more reliable. But I would like to fix this problem.

 

Found the problem. I had accidently cut a pair of ground wires under the coolant tank. I must have cut them when I removed the old tank to put in a new one. Now everything is fine and works as it should. I thought I found all the ground wires, but these were under the coolant tank and I had to remove the windshield washer fluid tank to get to them. There was no way I could get the coolant tank off. The tabs that secure it are very difficult to work with ( for me, somebody else might just pop that off with a screwdriver). So now I soldered the wires back together. I was going crazy thinking that I messed up the wiring replacing the alternator and coolant hoses. I took a week off thinking about the problem and just tried again tonight. Noticed the cut wires under the tank when I took out the headlight to recheck its wires. I knew a bad ground was likely the problem, but finding it drove me nuts. So the next time anyone replaces the coolant tank, just double check the grounds located near there.