2000 Taco cranks but won't start with AC&AC Fan turned on....

Hello All, I'm new to the forum and looking for some assistance. I've browsed the forums but have yet to find an answer to my specific issue.

Issue: 2000 Toyota Tacoma 4X4, 3.4 Engine, 5-Speed Manual Trans. Trucks runs but will die at times while driving with the AC on. When I try to restart the truck, it cranks but will not start as long as the AC & AC fan are turned on. If I turn off both, the truck will fire up. I can also recreate this issue while it's sitting in the garage, truck will be running with AC on, I turn off the truck and try to restart but only cranks unless I turn off the AC $ AC fan.

Things I've tried to correct the issue: Replaced the IAC, Cleaned the Throttle body, Cleaned the MAF, Replaced the Coils, Wires, Spark Plugs, Replaced the Fuel Filter and Fuel Pump Assembly, Replaced the belts, Oil Change, Antifreeze, (I know those last few shouldn't be part of the problem but just some info), Checked all Fuses and Relays, Disconnected the Battery for minimum of 10mins, Tried reading any codes but OBD II will not register connection to vehicle, Replaced vacuum and rubber fuel lines.

I believe that is all that has been done to try and correct the issue with no luck.

Does anyone out there know of this issue or have had it happen to them? If so, what did you do to fix it? I'm at the end of things that I know on what to do to fix it.

I would appreciate any help or advise anyone has. Thanks in advance.

 

This should be a fun one.
Let me look at some diagrams, and see where we can "start".

 

Out of curiosity, does pulling the 10A AC Fuse allow the truck to start?

 

And to clarify, it's with the fan AND a/c on or will the fan only not cause a problem. If so then I would maybe check the compressor relay and spin the front of the compressor by hand to see the compressor is seized

 

Ok, This has me wondering.
A few questions.

Does the check engine light come ON, with the key ON and engine OFF?

 

I haven't tried that as of yet, but I'm sure it would cause if I just turn off the AC Fan to where the AC green light on the button is off --- the truck will start.

 

If that fan is on then the truck will not start --- the AC compressor is not seized as the AC spins and it blows cold air. The compressor cycles just fine while it's running and I'm parked, (not driving around), but at times while driving the truck will die. Not start until I turn off the fan, which also turns off the AC

 

Yes the Check Engine Light comes ON with the key in Position 2 and engine not on. Also I tried starting the engine with the 10Amp AC fused pulled and the fan blower switch on and the truck would not start. I turned the blower switch off and the truck started.

 

Let me eat dinner and go over the diagrams.
The 10A AC fuse powers the AC amplifier. So I don’t suspect that is the issue.
It would be nice to know if we are dealing with a fuel or ignition issue here.
I’ll get back to you in an hour or so.

 

This is quite interesting

Will the truck start with the blower on and A/C button off?

Does it set any codes when it won't start?

Does anything else not work?

Also need to know if your truck is Federal or California emissions to look up the correct diagrams.
It will say on the emissions label under the hood.

 

The truck will not start with the blower motor on and AC button off. I can't see if there are any codes because for whatever reason, neither one of my OBD II readers are able to make connection with the truck at this time. The emissions is Fed and Canada. Everything else seems to work fine. Truck idles really good, seems to run good without the blower on.

 

Thank you.. The truck seems to have plenty of fuel pressure, and as I stated I replaced the fuel assembly and fuel filter because I thought that was the issue when this all started.

 

Ok I have a hunch based on the information we have.

Unplug the HEATER Relay and see if the truck starts or not.

 

I bet it will

 

I unplugged the heater relays and the truck would not start with the blower switch on or off -- replaced the relay and turned off the blower motor and the truck started. Turned truck off, turned blower switch on and truck would not start.

 

If I'm right it won't, I'll let you study the diagrams and see if you can figure out why.

 

Sorry bet not won ---

 

Well, the blower relay is GROUNDED when off.
So.......@dm93

Do we have a ground issue?

 

Ok do your right front park and turn signal lights work with the blower on?

 

Yes all signals and lights are working with the blower on. Also I checked all the charging system with my tester earlier today. Battery, Cranking and Charging all tested good.