My fans stopped working two weeks ago after I changed Opti and got my PCM resocketed. Today I did the following diagnostics:

1) Connected #5 and #6 pins at DLC- fans work
2) Checked all three relays with fog light relay- all 3 are good
3) Checked the temperature PCM sees with Datamaster- same reading as gage- all good
4) Checked both grounds for PCM and for coil- both good

Basically I am left with bad wiring or bad PCM, but my wiring was good before I got PCM resocketed. Is there any way to check PCM.
I am missing out something in my diagnostics?

One quick question for Shoebox (everybody else is welcome to answer it too)- if I connect blue (h) wire from c100 (http://shbox.com/1/fan_sw_diagram1.jpg) to 12V source from ignition- both of my fans should work at high speed all the time? If not, what I need to do that both my fans would work all the time key is turned at high speed.

Right now I just routed 12V from ignition fuse to fans- both work but low speed, and it is not enough sometimes in California

 

Noooooo...don't put 12v on that blue wire! A ground is what the relays need to operate them. Besides, putting a ground on that wire will not make both fans run. Both green and blue must be grounded for both fans to run at high speed.

You jumpered 5 and 6 on the DLC and your fans worked. It's because the PCM told them to. Monitor your PCM with a scanner and watch when it indicates the fans should be on. You then need to monitor the green wire and see if it gets a ground from the PCM (make sure you monitor the green wire's potential ahead of time, so you can easily tell the change).

 

thanks shoebox I will check if the green wire gets ground tomorrow. I wish the Datamaster could show if fans are on

 

Datamaster does show when the fans are on.

 

I am looking at datamaster EE 3.4.1 right now, but I don't see the fan indicator.
On the top right I see

0 A/C clutch 0 P/N switch
0 A/c request empty
empty --
-- --
-- --

Maybe I am looking in the wrong place

 

You do know that you can custom configure those monitors to anything you want, right? (maybe not) Double click the name, then select from the list.

 

Yep you were right shoebox, as usual. Looks like my PCM went bad after resocketing. I have files from before, and it clearly shows that at certain temperature my PCM would command fans to come on. However, the current files (after resocketing) don't do it anymore. PCM never orders fans to come on

 

Maybe the fan ON temps were changed with some programming?

 

Not really, fans are programmed to kick in at 178. I even let my engine go to 220, still no fans

 

Do you have the software to look at and veryify the programming? What I am saying is maybe there was an error made when it was programmed. Maybe it was set at 278 or a typo like that.

Or...maybe it was never changed at all. Try letting it get to >226 to see if they come on. It may still be set at stock.

 

It is a possibility. My C.A.T.S started requesting for some password, never did it before . I will see if it is the case. It is kind of painful to let my car to go to 226, but I will do it. Too late to do it today, I live in a very quiet neighborhood

 

Yep, it was programming issue. After resocketing my PCM only takes Celcius temperatures , so my fans were set to come on at 97C and 102C which is boiling point for water, freaken high. Now I set my fnas to come on ~ 80C and it works

 

There you go!