Alternate Blower Job

No not what you think. So after taking out the alternator again took it to the shop. Bench checked it and it's okay. Metered the 3 connectors (S<IG<L) in the plastic connector all 12v. Noticed something new though... At idle it meters at 14.4v but the RUB is that when the fans kick on that is when the volts drop to mid 13 and the dash light starts flickering. When the fans shut off the volts go back up to 14 1/2 and the light goes out. OR, pushing the idle up to 2,000 RPM or higher it seems the light goes off too. If the fans are offI can turn on the lights crank up the radio put on the a/c still fine. It seems it's those damn FANS! So, how do I check them and what am I looking for?
OAWG - Once again with my gratitude

 

Ernie, No Doubt, BillyBob, Todd? Anyone?

 

Thanks Pap, we can always count on your sage advice. I'll check it out and post results. Seemingly I can move past the alternator for now, at least I've gotten much faster at taking that damn thing in and out so many times already!

 

Pap says :"Check with an amp meter to see how much current draw each fan has and compare both sides. "

Not sure how to do that since new to using the meter but, tried something a little different. I know how to do the volt check so I have an extra battery on hand so I metered the battery [11.72v] and connected each of the three fans and checked again. The two on the right had the volts go from 11.72 to 11.42 when running, the one on left 11.72 to 11.29. Since they all seem to spin freely (?) is this an indicator that the left hand fan is the likely culprit?

 

when I say running I mean off the spare battery not engine running...

To help me understand the process, the meter has
200mv to 600v from 9 to 12 o'clock on the dial
200 to 2M from 6 to 9 o'clock with the ohm symbol
600 to 200 from 1 to 2 o'clock with a V and a squiggly mark
and 20u to 10A from 2 to 5 o'clock

10ADC is the left socket
COM I know is the negative lead spot and
V OHM mA on the right which I am using for volts

 

Okay, it does look like there is a sticker on the back of the fan that has "40A". I thought 40 amps was too high so it did't occur to me. They do seem to spin freely to me or at least all the same but it also seems clear that the volts drop way down when the fans kick on and that is what triggers the dash light. So you're saying that without checkiing the amps there is still no clear answer right?

 

That's funny, I always do my best to work toward the redline
The bench test on the alternator showed 100 peak amps as the output

 

Pap, I don't know the condition of those since I did not do the rebuild. What I was planning today was to temporarily wire in a switch for each of the three fans to be able to shut off each one at a time and watch the volt meter and dash light. Wouldn't this help identify which one may be the culprit? Still don't have an ammeter.....

 

D, I'll cehck the records but don't know that it wasn't the original alternator. If the car is 17 years old I can live with 5-10 years on this one. Do other 348-ers swap out the Denso for another? A higher regulator? What is the better solution?
When i said peak 100A I think the shop's meter maxed at 100 so pinned on their dial could have been higher ? I did buy an ammeter today so I think I can check the output line on the alternator also and the meterr goes to 400a so it should read it correctly. We'll see the saga continues.

 

Okay D, new wrinkle. Got it all set up to test and the driver's side fan reads between 13.5-14.0; The passenger side top smaller fan seems to read between 6.3-6.5A; the lower passenger side fan reads zero because it doesn't come on. Curious because when I hook up an external battery it does in fact run. Didn't think to check the alternator positive cable but I can if this information is equivocable

 

There seems to be a 25A fuse for the left hand fan and a 20A fuse for the right hand fan (why can't they say drivers side and pasenger?)

Which is right side and which is left?

There are "control relay actuation" for left and right side. Replace all fuses and relays?

Can they be tested while I'm waiting to order new ones?

Does the passenger side fan only come on as temps go higher (aka, backup fan) or are they supposed to run simultaneoulsy on a 1995 348?

Is it more likely a fuse or a relay or a temp sensor?

 

but what if you're left handed? just kidding. Bought two new relays and a handful of fuses today so I'll just replace the two relays and fuses for both sides and see what happens. Since I know the right fan works when poweered directly and it doesn't turn on with the others I'm "hoping" a simple fuse/relay swap helps out. Still doesn't make sense to me that the draw on the alternator and battery would be worse if a fan didn't come on? Oh well, in electric world not a lot of things make sense.