96 q45 starting problems

[hal90000]

Seems like I have seen several posts about this problem, but I can't seem to find them.

I have had very intermitent starting problems with this car over the last year. I replaced the battery last spring. This seemed to have fixed the problem, but then again it got warm then too. We had a cold snap the night before last. Down to about freezing. Go out to car, attempt to start, no turn over. This is just like last winter. I charged the battery on a 2 amp charger all day, about 7 hours, car started fine. Get up this morning wont turn over. Headlight dim badly when on and attempting to crank. I saw several posts about the blue relay, but I can hear it click when the key is moved to the start position. I only drive the car two or three times a week so it doesn't get a lot of use.

I used a multimeter to check current draw. It was set on the 200m scale of the DCA function and was registering 190 or so. Is this the correct draw when the car is offf. Seems like I read it should be less than 100 but I don't know my scales well in electrical terms. Any sugestions or corrections? Thanks in advance.

[hal90000]

Just saw Q45tech post to a similar question in the Yahoo user's group. He said 80 milliamps on the draw. Looks like mine is over twice that. Time to pull some fuses I guess.

[DAEDALUS]

190mA is not enough on its own to cause a no-start after a day. Perhaps abnormal, but not a lot of current...sounds like the battery is on its last legs.

A good battery should be around 12.6V, car off. While cranking, it should stay above 10V. With the engine idling and all lights/accessories on the battery should measure 13-15V. Below 13, suspect a bad alternator or something is taking more than its share of juice.

Leave the ammeter hooked up with the car off and unplug fuses/relays to see how each contributes.

[hal90000]

I thought that if I had just barely reached the threshold of charge where the engine cranked over and started, but not yet a full charge, that it might discharge enough over night. But, then again, last night it cranked over real easy several times.

I think I measured the battery voltage at just over 11. Last time I checked voltage while running it was over 14 but that was last spring. The battery is only 7 or 8 months old.

[hal90000]

Ok, I started testing with the multimeter and found that the draw was alternating between .16 amps and .25 amps. (had to go to a different scale) This got me thinking about the security system as it was flashing in the same rhythm. The Security light flashes all the time. I checked the owner's manual and it said that the Security light should go out after thirty seconds after it is armed. Mine doesn't. Is this correct? My Mazda light flashes all the time hence the confusion. So I guess the security system is not functioning correctly.

The FSM says to check at connector M118, the BCM connector. Not an easy thing to do but I did get the connector off but had no luck with testing. All pins I checked, hood switch and trunk switch, were open. No conntinuity. The pins are kinda hard to test in the connector. My probes on the multimeter might not have been making good contact. Anyone have any hints? I ran out of time.

[qship96]

flashing light means one of the contact switches is faulty,check all doors,trunk,and hood switch-one is faulty!when corrected,the light will stay on for 30 seconds after closing and locking all openings,then go out.

[hal90000]

Thanks for confirming. I think I will move my testing from the BCM connector to the actual switches. Seems easier as long as the wiring between the switch and BCM are good.

[Q45tech]

The hood is open and thus the system won't arm thus the changing current draw. The 94+ consumes more current due to body control memory!200 millamperes is ok ............5 AMPERE HOURS per day should allow 10-12 days with a brand new battery of the correct size and quality.

If the battery with everything off doesn't read 12.6 volts its not 100% charged! 12.3 voltages can be 50% charged depending on temperature and battery.

http://www.homepower.com/files/battvoltandsoc.pdf

". I charged the battery on a 2 amp charger all day, about 7 hours, car started fine." That is ONLY 14 Amp hours....[maybe 7-10% recharged]......it might take 50 hours at that low charge rate

[hal90000]

The system never arms on my car regardless of if the hood is down or not. But it is good to know that the 96 does consume more energy at rest than I read in another post. They must have been working on an older car. I am going to continue checking the switches on the security system.

I will check the battery voltage more closely and make sure it reads and maintains the 12.6 volts you mention however long it takes on the charger.