Spike
If you had access to a clip-on AMPPROBE that you can clip around each wire you could isolate were the draw is coming from. I know it's tight in there but some of the fan wires are accessible. The coolant sensor tells the ECU to turn on one or both fans and at what speed through RELAYS which turn on one or both fans depending on engine temp. and if the air conditioning is on. This should eliminate a lot of testing, there is minimal amperage in the control circuits but from the relays to the components(fans,lights,motors)the amperage is obviously higher. Pull a fan relay and see if the problem changes,swap it with another one. sometimes the component is powered then controlled by grounding so check your body grounds. Is there a draw when the key is off, does your battery go down over night, if not it's probably just a to high a amperage draw from a component like THE FANS, like Chris said you could be looking past the actual problem, it is easy to do, 90 amps is a lot of current to be using on fans without something burning out eventually.

 

Thanks for the reply. The battery does not go flat while the car is of, so this is not a parasitic drain, it's only at IDLE with a full load (ac, all lights, etc) on.

Please forgive me if I am not understanding, but you are saying that our theory is correct?.... Right now we have measured the fan drawing close to 90 amps and getting very hot. We are thinking that because it's pulling so much more than it should, the alternator can not handle that plus the a/c, lights etc, so we are thinking the culprit is the fan module,,,, OR are you saying that you think we are looking past the real problem. Sorry, I probably am loosing my ability to reason

All help greatly appreciated.

 

Isn't it an 80A fuse? And the design would be for 80A to be conservative i.e. never draw more than (say) 70-75A normally. So 90A says something is faulty, like a worn fan motor or bad module.

 

Hello all,

My mechanic compared what my cooling fan was pulling to other X's in his shop and he said it was fine, what was actually pulling an insane amount of amperage was the A/C OR HEATER FAN, which he tested by isolating from the rest of the system. He says he filed cleaned all the connections on that a/c fan and now it does not pull that much draw, still a little high in his opinion, but not too much over what it should.

Yesterday he left the car on for 1.30 hour at idle to see if it would die. It was fine. Today he left it in with a full a/c headlights front and rear fogs for an hour and it did not die. I have now picked up the car ...BUT

I am very nervous driving it. Was this A/C or HEATER FAN really the problem?? Like I said before, there was RAIN water dripping inside the cabin on the passanger side from a windshield cowl leak before......I guess it could have dripped into the blower fan connector and caused some resistance...

What do you all think?

 

Drove thru 5pm rush bumper to bumper traffic and car did fine, no stalling.

I am just having a hard time accepting that a blower fan connector was causing to much resistance that it was draining my battery at idle.

 

Steve
You are not loosing your ability It's that your getting information overload with a problem that is complex and and if not dealt with soon and in the correct manner it can cost a lot of money, I feel your pain (done that). Anyways I'm glad you have some sort of handle on it. I still find it hard to believe that a BLOWER MOTOR would draw 90 amps and not roast the wires. Now a radiator cooling fan can draw a lot of amps but a blower motor.I would defiantly seal the windshield cowling so water doesn't run onto the ECU and the floor.

 

Got to work during morning rush hour with no problem. Last night I looked under the footwell and saw the a/c or heater blower fan and it's connector. This is exactly where outside rain water was dripping into the car when it was raining hard before, so I think that the problem was indeed resistance of te blower due to water ingress at this point.

I have already tried to seal the windshield cowl the best way I could, but I may try to get a new one just in case.

 

Spike, welcome to the wonderful world of electronics and modern day electricity. Sometimes the strangest things happen and you just have to accept what the facts tell you. I wish I could give you a better answer than that, but I have seen stranger things happen.

 

Indeed. I just hope the problem does not come back

I may replace the blower with a new one just to feel safe driving the car.

 

We'll it's been six days of rush hour traffic with lights and a/c on and all is normal. No battery light or stalling of any sort. Hope I am not jinxing myself, but verdict seems to be water leaked into the blower connector and caused a whole lot of resistance. Then that coupled with full load of lights etc was too much on the alternator. All new battery, alternator (aftermarket), battery cables, and of course filed contacts on electrical plug to blower, plus clear silicone to seal any potential water ingress on windshield cowl,and all is normal.

I should note that we tried 2 aftermarket alternators and the first caused the battery light to come on immediately and seemed to have been a dud. Obviously (read above) the second aftermarket alternator is not doing any of that.

 

Oh no!

3 months after the last post on this my battery light came back on.

I washed the car earlier today and parked it. I turned it on a few hours later and the light was on. I could not find any water in the blower connector, which was the culprit last time for pulling too much amperage, but I imagine that this is related to water again. I left the car on for a while and it did not die, but this is how it all began back in Novemeber. The only other thing is that coolant has been driping on the new possitive battery cable due a very small drip on the coolant hose. U don't think a few drops of coolant have destroyed the cable. It does look good on inspection. I ordered a new hose last week.

Last time this took lots of money and time to track down. If I can't fix this myself, as much as I like this car, I am going to have to replace it with something new. It's my daily driver which I use for work. I really can't drive clients around in my E type or XJS if I need to.

Help !!