I've read RAVE, I've looked at the confusing high speed/low speed fuse box relay circuit and still have no idea why my low speed fans don't run. If I jump 13/14/18 relays both fans run, if I use Nanocom (GEMs ECU Output Function) to run low speed AC fans they both run. On a 40degC days here stuck in traffic my high speed fans run but never the low speed. My AC works well but even with a new fan viscous coupling the performance drops at idle. As far as I can tell there needs to be an HVAC low speed fan request, a GEMs fan request (for 12V and Ground) and the the two way/low speed AC pressure sensor needs to be closed. Suspecting the HVAC controller output but does anyone know when the HVAC is supposed to request low speed fans so I can check the output? Thanks - going crazy on this one.

Hi All, new member here so hope this post is okay. I've got a 1997 GEMs 4.6L that runs very rich. Using a Nanocom I can see my short-term trim is 38 and my long term trim is zero. Both O2 sensors appear to be working and with light driving they run at around 4.6V to 5V and both banks run in a similar way. The MAF seems fine - sensible voltage and mass flow numbers and so does the TPS. I've tried resetting the adaptive, but the P38 always returns to this high short-term trim number. I always run a minimum of 95Ron but 98Ron makes no difference. Any idea what I should try to fix this? So far I've cleaned the MAF (with MAF cleaner), changed all the plugs for NGK plus OEM leads - the original plugs were the richest I've ever seen on a fuel injected car! My next step would be to change the O2 sensors except they seem to both be working. Any help really appreciated!