More fun with Fan issues... Different car...

[Corvette95]

Does the tech one show fan command on? (not in field service mode) . Hook up Tech1 and turn a/c on. Does the Tech1 show fans requested on?

[LGAFF]

This keeps just getting better; just put in a different ECM and the same issue

[LGAFF]

So today I discovered that a on 90 and 92 the Tech one fan test mode works, but apparently not on a 91... Last year I took the car off the rack for a trial run after putting it back together, the fans did not come on and the car went up to 230+ degrees(tuned to turn on early)...so I shut if off and put it back on the rack in the garage

I got my tech one out, and tried to force the fans on, didnt work. I tried it on my 90, it worked... so went back to my 91 swapped the relays, still couldnt force them on.... put the car away until this year.

I had some time to work on the 91 again recently, tried the tech one on my 92 it worked to force them on... so I went back to the 91 tried to again always the same symptoms the relays would click, both primary and secondary fans would even turn on for a second or two sometimes..... I went through ecms. proms checks etc.. 90/92 eproms in the 91 always worked fans when placed in the 91... any 91 prom would never work, stock modded, etc

So today, took the car back outside... swapped the relays and what do you know they work, came on at 207

So big error on my part in assuming the Tech One inability to turn the fans on was an indicator of the problem with the car .....

[XfireZ51]

Wonder if u can confirm w someone like Marc.

[LGAFF]

Marc doesnt use a Tech One but he was nice enough to help me with prom testing....I got too stuck on my fans dont work and if it cant pass the test mode I need to keep looking vs retesting with a running car.... My assumption was if the fans work in my other two and they both allow the fans on then obviously I still have an issue, repeat.... hey it runs and the car is not mechanically completed....

[Corvette95]

regardless, I am glad you got it fixed. There is no known reason the Tech1 would not work as it does on the others. I wonder if you have a connector problem with the ALDL port on the 91. Also, I have had issues with an Tech1 cartridge having program issues. I assume you are using a Mass Storage Cartridge in your Tech1. When I was asking out the Data list showing the fan command, this is where I starting to troubleshoot. Good job on finding the root issue. Maybe next time you are with someone that has a Tech1 you can try theirs on your 91, unlikely but have seen it happen with a going bad cartridge. Also, may try using the 90 or 92 VIN on the Tech1 when connected to the 91.

[LGAFF]

The Tech one worked on the 90/92 and also the Tech one worked in the 91 with any combination of ECMS and even 90/92 chips in the 91 car, odd....

its in my video test....

Thanks for everyone for their input

[XfireZ51]

Lee,

I have a Tech One. Maybe we can try that and see if it is a Tech One issue.