JBJrC4

91 6 speed. My primary fan seems to turn on late (picture below) Or is it normal
? Anyway, my secondary never turns on. Not even with the AC on. When I ground to check the codes they both turn on so I know the secondary works. Any help? Thanks.

billschroeder5842

Joe, it sounds pretty normal.

BTW... you analog gauge is a "close representation" and not an exact measurement of your temperature. T.o double check you should hit your engine with a thermo gun

JBJrC4

Good to know. So what about the secondary fan? Isn't it supposed to help the primary fan with cooling the radiator or block?

PatternDayTrader

It doesn't come on until 228. Your pic looks normal to me.

JBJrC4

It never came on though even when it reached that temp.

RollaMo-LT4

How do you know it reached 228?

That analog gauge does not have a linear scale, and it almost impossible to tell what the real temp reading is.

Unless that needle gets close to the "shaded" area of the gauge, you probably haven't reached the trigger point of the fans.

gdgeorge

I had an issue with the secondary fan not coming on in traffic in downtown DC in the summer. (All I had to go on was the digital readout and the gauge, so I spent a bit of time sitting (in DC, on some not-so-great looking neighborhoods) with the engine turned off and the hood up to cool things down until I could get back on a faster road.

Turns out that there was a code in the system for the quad driver module but it didn't turn on anything on the dash to tell me that. I took the car to a local mechanic and he diagnosed the issue as a bad fan relay (which *would* set the QDM code...) On advice from an older "Chevy Guy," I had the mechanic wire past the relay and put an analog temperature probe into the block to switch the fan on. It's worked for several years now and is apparently a common enough fix that Chevy "has a kit" for this problem.

If I had it to do again, knowing what I know now, I'd probably have had the mechanic track down specifics and fix it the way the system was intended to operate. Actually, I'd probably do it myself... But that was then and this isn't.

Regards,
Jerry

johno504

check the 40A fuse in the small box just under the brake booster. with this fuse blown secondary fan will never turn on. found this out the hard, expensive way last summer. $800 later, all is good.

JBJrC4

I don't see a box under there?

johno504

perhaps a 96 is not the same. my fuse box is about 1 1/2 wide x 5-6 inch long located left front under brake booster. find Your secondary fan fuse and check it. when I was having overheating problems it took a THIRD ! mechanic to find fuse issue ( he owned a 96 ).