well hmmm ive been fiddlin around with my issue of a battery drain ONLY when using A/C while my 03 disco SE is running... i did in the past have to repair a shorted wire to resistor but that was years ago and everything has been fine.... i have however gone through a couple batteries since then... and last year my battery went out and i bought another and it worked but when A/C would be on it would run hot but always started... recently is been acting funny and i noticed voltage dropping... come to find out after getting stuck with dead battery that alternator had gone... I replaced it... and now is working great... 13.7-14.2 ... EXCEPT! when a/c is on... then it drops until car won run and seems o run hotter.... next I put on ECON so no compressor and battery still draining... im staring to think it is the A/C Blower or resistor?? can they fail in a way that they can draw enough to run down battery while driving?

 

Strange as when running your alternator should handle the load and not a draw on the battery. Have you had your alternator looked at?

 

Test the Output of the alternator with the engine running by a meter. Engine off battery should be 12.5 to 13.0v. Engine running it should read 13.4 to 14.1v

 

yes I have an ultragauge and when running it is nice and high around 13.8-14.2 generally occasionally dips down to 13.7 with new alternator.. I always monitor it.. and since i did have abad alternator i changed it and everything works great and reliable voltages but if I run the a/c for even 1 trip 6 miles to work.. i see it dipping down to 13.5,3,2 and then when i come out after work it wont start without a jump

 

im wondering if it is the climate control module.. ive read some stories of them killing a battery ? with that unit off i have zero issues

 

Check the ground cable, where it attaches to alternator bracket on engine. If you don't have a good ground, the alternator's performance will be diminished. Also, make sure battery terminals are clean and secure. If the alternator is working properly and all ground points are secure and corrosion free, it should have no problem maintaining accessories and recharging the battery.

And what do you mean by..."it seems hotter"? If you're talking about engine temps, either it is or it isn't. You need to verify engine temp to be sure. Unless you're talking about "under the hood" seems hotter, when opening while A/C is on. Then that could be caused by the A/C condenser, it becomes quite warm while in use and will raise engine compartment temps considerably, and this would be normal to feel slightly warmer.

 

I ok what I mistyped ( thinking out loud) was that it does run hotter.. im running the cooling line Mod for years and is always ran very cool... running temps 188-194deg F with a/c on maybe 194-203.. but with a/c on it starts creeping up around 210-212 and by that time I decide to turn off a/c and it goes back to normal... i run a colder thermostat also with the mod as many have done... a/c does blow pretty cold and works great in Florida winter were its not 100deg and in winter still blows cold just not super hair whipping circulation so its never like a chevy a/c lol but its comfy and climate control seems to work... I was having a terrible time getting the climate control module to switch back to F from C but i ran the diagnostic and it showed to be ok on the unit.. im not sure how smart that diagnostic is though... anyway, whatever is happening, no matter what other lighting i run, or accessory or anything, its fine.. only if I turn on A/C do i start having issues... the other oddity which ive asked around but still havent solved is when i turn on headlights brights, my windshield wipers come on lol

 

Does the Efan in front of the radiator cycle on? I've heard of some people having issues with it drawing more AMP's than usual, but when it does that (efan going out) it will usually pop the 40amp fuse however not all the time. You could pull the fuse and see if the draw stops.

 

Yeah, l gave the electric fan a thought too, but like mentioned by Best...it usually blows the fuse. You could pull fuse and see where that takes you. Granted, you are seeing higher temps, so be mindful of that.

Did notice similar conditions on my 04, A/C on and temps crept up to 214 at idle quickly. Drove my wife's 03, under same conditions (same day, same route, 89F) and her's never got above 204 while idling (even let her's idle an extra ten minutes). Electric fan was working, so l checked the viscous fan...and was not feeling any resistance when warm/hot. Changed fans with a spare, out of my 01, and temps mirrored the 03 (204). Both have 180° stats...and go down the road at 186°.

Yes, l get what you're saying about typing what you're thinking...do it often...and it makes little to no sense...lol.

 

Ive changed viscous fans a few times even went with the 02 version with a chevy HD fan clutch and it WHOOSHED a few times the stopped WOOSHING at startup but temps seemed ok... its possible I got a lemon just compounding my diagnostic.... however I did have to replace the wire ( splice it) few years earlier because it shorted and fan stopped.. when I repaired the connection the fan worked .. so maybe the 40 amp fuse didnt blow and maybe something going on with the fan