One cooling fan turns off when high speed turns on

I have checked all the relays and they are all good. What I have discovered is it appears I have no power coming out of the 30 slot for Fan Relay 2. Evidently that relay is bypassed entirely in low mode and both fans are run in a series just using Fan Relay 1 so that they only use 6 volts each. Fan Relay 2 is only used in parallel mode so both fans can get the full 12 volts for high. The 87 slot is grounded so I am now looking at the 30 slot on the fuse block for Fan Relay 2 to find out why it's not getting any power. Any advice still appreciated.

Hello, here's the #2 fan relay, powers from Cool Fan 2, fuse #18 30amp.

It looks like Cool/Fan See/Par relay #29 is turned on with the #2fan relay both by grounding by ecm. Also notice that Right Fan has a diode directing current. I would check that as well. I'm impressed that you figured all that other info on the fan circuits. Nice work.

Here's the entire circuit if you need it. Let us know what you find.

Thanks you so much for the diagrams, will be very helpful. Had to do a bit of research throughout the day so learned a few things along the way. :)

I see that diode is on the 87 side, not really sure how that would have an effect on the 30 slot not showing any voltage. i was checking directly into the slot with the relay removed. I tried and tried to find 12+V coming out of the 30 slot and got nothing. The #1 relay shows power at the 30 so I figure the #2 should act the same at all times with the car running. Everything else I tested was fine.

Now if I can get the fuse box up and out enough to investigate that thing. That did not happen so easily..... I gave up on that and it got dark so seemed like a good time to walk away until morning. I will report back for sure. Thanks again for taking the time to help me out.

Absolutely, if you need anything else just let us know. Have a good night.

I do have a question. Do you have any suggestions on where to start if you had narrowed an issue down to the point I am at currently? (Trying to find out why I have no power at the 30 (power side) of the fuse block for the #2 relay?) I tried to see into it to see if the contact was gone but cant tell..

I would take the fuse block up, most likely you have a corroded broken wire under there, and if not, trace the wire back to it's fuse and then its original power source, such as a splice or wherever it goes .fuse #18 I think it was. It's on that diagram. You'll find the problem, you're on the right track.

It ended up being the J Fuse to Fan 2 (#18). I got a little caught up in the way the system works and overlooked the simplest of things. Thank you again for your help.

That's great news, it was something cheap to fix. Nice work. Cheers