Fan Problem

What would cause the cooling fans to come on and off? It does this no matter how cold or warm it is outside. Even at idle. When I was driving to work, about 20 min drive, it never went above the dash right before the C. I know my gauge works, and the sending unit. I have a problem with the VAM right now, so I don't know if it is throwing a code to switch the fan on and off.

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'88 Black, K&N on VAM,
T-3 set at 22psi, ported E6, 2.5" single cat-back w/dynomax muffler, gillis, RR, TA cam gear, Bosch BPV

There is no way a VAM problem would affect the fans in any way. Are you 100% sure your temp gauge is working properly.... they are highly inaccurate.

When you say fans, do you mean both turn on or just one? Both fans should not turn on at the same time. Are they (or it) turning on and off with the HVAC controls set in either MAX or NORM A/C or in MIX or DEFROST? In MIX and DEFROST, the A/C compressor will cycle if outside temp is over about 45 deg, and the main fan runs whenever the A/C compressor runs. THe aux fan should only run with the A/C comp if high side pressure exceeds 310 psi, which isnt likely to happen ulness temps are 90 deg +, or the high side has a restriction like a plugged orifice tube.

If the fan or fans are running / cycling with the HVAC in OFF, VENT or FLOOR, the ECT may be bad and telling the EEC coolant temp is much hotter than it really is.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 02 Taurus Vulcan(wifes car)

I know my gauge works, cause when I was going to work, it read cold and the heat was cold. I'll have to double check, but I do beleive the pass. side fan runs off and on when the HVAC control is off. I changed the ECT last year. It actually just started to do this. I also chaged the Intergrated module on the fender well, last year with a known good one. I think I'll try another ECT, any more ideas?