This is my first post on FTE, my apologies that it’s so long. I would really appreciate any ideas or opinions about my situation and thanks in advance for the help.

The car:
2000 Mazda B2500SE 5Spd. with 56400 miles. Aftermarket stereo and professionally installed keyless entry and power door locks.

The Problem:
Since I got the car new I have had a few electrical problems. Some of my dash lights are out, I seem to have the sporadic door ajar problem and my heat stopped working, which also seems to be common in these cars. However, my biggest problem is that I have had the alternator fail 3 times now and this time I’m out of the regular warranty. The previous times they replaced it and the battery without even mentioning that it could be caused by something other then a faulty alternator. This time however, the service manager was trying to make it seem like it was my fault by saying “well, if the cars been in an accident or there is some type of grounding issue you’re probably going to have to pay to fix it” I know I haven’t been in any accidents and if it’s a grounding issue they should have found it in the first place.

My Concern:
I have a gut feeling that they are going to say it’s the aftermarket keyless entry system I had installed when I got the car. I spoke with the shop that did the installation and they said it’s very unlikely that it’s the alarm because it only draws ½ an amp. Also, since I am out of the regular warranty, but still within the 1 year 12000 mile since they replaced the alternator/battery last time, are they going to give me any trouble about covering it this time? And is it possible that the heat not working is somehow related to the alternator?

Thanks again for the help!

Jon

P.S. Has anyone else had this problem???

 

the heat not working most definitely could be the problem! If you had a weak short in the heater system it could draw a low amp drain. If you don't have the elecrical experience to test for a drain, unplug the heater and see if it goes away.

 

Thanks for your reply!

I don’t think the heat is necessarily the culprit, because the first alternator failed over 2 years ago and the heats been on and off working just for the last year. I was thinking maybe it’s the other way around, the alternator damaging the heat? Anyway I should hear from the dealership today and we’ll see what their story is.

Thanks
Jon

 

What are the symptoms of the heat not working? Does it blow air, just not at hot temperatures? Cold temperatures? Only on certain fan speeds? Only through certain vents? The temperature could be an electrical problem (air blend door actuator) or a cooling system problem (no coolant in heater core or AC system problem). The fan speed is electrical if either the fan doesn't blow at all or only at high speed and not at the lower settings (resistor network). All the vents selections are done by vacuum.

Door ajar/dome light is probably the same issue everyone else here has complained about. WD-40 or contact cleaner on the switch sometimes fixes it. It may have been exacerbated by your keyless entry system installation.

Was the alternator actually bad the last few times that they replaced it or was it just a preemptive action because the battery was dead? Have they checked the regulator (I don't know if it is seperate or not)?

1/2 amp is a lot of current drain. If you leave the truck sitting drawing 1/2 amp for 2 days, you've drawn 24 amp hours out of the battery. I checked Interstate's spec on a Ranger battery and they have a 90 minute reserve capacity. This is how long the battery will stay above 10.5 V (for a 12V battery) with a constant 25 amp discharge. This is 1.5hours*25amps = 37.5 amp hours. Now, you are drawing far less current, but over a much longer time so as you can see you could really put a dent in it, especially with many cycles of doing this. Automotive Lead-Acid batteries are not meant for deep cycling and will wear faster if they are.

You could still have a short causing the problem. Let us know what the heater problems are so we can venture a better guess as to whether they are related or not.

-Jim

 

I just got off the phone with Jim (the service manager at the dealership). Seems to be good news, he said that the engine harness was totally corroded and they will get the new one tomorrow. He also said that the battery was shot and they can’t test the alternator until they have the new harness. It sounds like this part of the problem should be covered under the warranty .

As for the heat, all I get is fresh air or A/C but nothing hot. There is definitely hot coolant flowing into the dash from the engine. All I can think is that either the blend door is stuck or the motor that moves the door is somehow fried.

Thanks
Jon