Hi all,

Proud new owner of a 92 here. Love her dearly, but…

having overheating issues. Secondary fan isn’t turning on to cool the car. Nor is it turning on when the AC should engage it (has the damn climate control system, so no positive AC control).

Brought it to my mechanic who tested everything from ECM to the fans (first time owner, didn’t want to fiddle too much by myself at first inspection). Relays, wiring, etc., all good. Diagnosis was that the ECM programming must be bad, isn’t sending the signal to the relays to ground out, and turn the fans on.

Got the ECM back, reprogrammed, and problem persisted. Thinking it was still the ECM, somehow, sent it out to have the physical unit itself tested/refurbed. That vendor determined there was nothing physically wrong with the unit. And they performed a bench test, wherein they determined that everything was functioning properly (and, presumably, that proper codes for the fans to engage were being sent).

So, I got it back, plugged it in, took her for a ride. Within 5 minutes she overheated and shut off. Fun… but, I noticed the Digical readout only said 198-ish (I’ve already learned not to trust the analogue gauges…)

Afterward, I dug in to see what might be up, after doing some extensive reading here on the forum.

Ground out the relays to test that the fans were still good: All Good

Jumped the A&B pins on the ALDL: fans turned on

Noticed, however, that on my Climate Control dash thingamajigger it reads (and always has read) 69* outside. Since it’s mid June, that’s obviously not accurate.

That got me to thinking, maybe it’s the Temperature Sensor? Don’t particularly know that the outside temp read relates to the engine temp reading-process at all, but at this point it’s all I’ve got…

All that said, does the ALDL interface from the ECM? Wondering if the fact that it works when I jump the A&B negates the ECM potentially being the problem. Which, again, lands me back at the Temp Sensor. Maybe it’s just reading the temp too low, and never telling the fans to engage. And thus also why it never thinks it’s hot enough in the car to start the AC running…?

would greatly appreciate the community’s thoughts here. Running out of “right” solutions before I just go ahead and wire in some kind of bypass thermostat that grounds the fans relays outside of the ECM system…

thanks!

 

Follow on question:

If I jump the A&B pins, and drive around, will the Corvette gods smite me? As a temporary workaround?

thanks again!