overheating and fans not coming on

Is there a fuse connected to the fan? if so, check that first. Can you bypass the thermostat and see if the fan itself will run? If it does and the fuse if there is one, is good, the thermostat may be the problem. That is a common problem, especially in the lesser style electric radiator fans. That is why I bypassed my thermostat and put an inline fuse in. the fan runs all the time, but in a hot climate that is OK.

Computer chip under the passenger side glove box, $500.00 new. Told it should turn on the fans automatically, haven't tried it yet myself. I need to turn on the heat full blast in a drive through or my engine will blow up !!!

replace your cooling fan sensor switch located under the trotlle.

Check for air in the system a far as it overheating the problem is air goes to the highest point in the system and the bleeders are below that .I put in a prestone filler in the hoses that go to the rear heater and I hook the hose up to it on a trickle I have emptied and filled my radiator with straight antifreeze I start filling the system until there is no air coming out of the bleeders and then i start the car you must have good heat in the front and rear heaters for it to be full otherwise it will get air locked also check your temperature switch

I think chevy designed the electric fans to come on at 230 way to hot i used to run my ac and fans would come on you got 2 30 amp fuses and 3 relays and a temp sensor under thottle cAble but they had a problem with dexcool eating intake gasket i flushed that out and put prestone mix with any kind but as far as air you have a bleeder valve above water pump open that up when running to bleeder air then do the same with bleeder valve by themastat

I used to turn the AC on number one speed so the fans could come on doesn't come on anymore, why?

Your sensor leading to the fan switch is bad. Perhaps the entire fan system needs to be checked out, and replaced if needs be. Check for lose wiring and or bad connections of the wires. My bet would be a sensor or switch relay.

If your relays and fuses are working and replaced the Thermo Fan sensor Switch and if your car is still overheating, then check your cooling fans. If your cooling fans are not working even after testing each individual fan then it's time to replace the fans. If you have no leaking of the cooling/heating system you can also, replace the thermostat. Hey before doing anything on your car first bleed the cooling system that usually corrects the overheating problems. GM 3400 engines Chevy Venture

how do i check my cowley fan if working .want to connect to a on/off switch

On my mom's it had this problem found a shop in Oregon fixed said when Ac was low or had a leak it had a fan override and would shut the fan off. Fixed Ac and it started working

What about engine overheating?3400 c.id. engines are known for head gaskets

I have the same problem with my chevy Venture 2003. First check your temp sensor/switch located next to thermostat, next check your 3 relays for cooling fan and 2 fuses, NEXT use to wire to bypass your relay to make sure that Fans are working. Last your ECM sending command to turn your low and high speed fan.

I can tell you this much I have had my Chevy venture for a long time about 10 years, about 3 years ago it started running hot and this started a very long pain in neck problem. I replaced the heat sensor, thermostat, and water pump, but still it ran hot I didn't think the head gasket was bad because there was no water beads on oil stick, and it didn't have a water drip on the ground. Now my venture has 2 air bleeders one on each side of the motor, one close to thermostat and the other one just above water pump and learned how to bleed it on line and for about 2 years this is how we drove it. When it started getting hot I had to pull over and bleed the air out. There was a few times it got really hot and I guess that caused the head gasket to blow. I had the head gasket replaced but still it ran hot now this was after I had replaced everything that had to do with the problem of it running hot. I took it to so many garages I lost count, then one day my rubber hose that goes to the bypass waterline for the heater in the back of the van busted and I had to replace it and that is when I discovered 2 very small pin holes in the aluminum bypass line it was not leaking water out but it was sucking in air causing a air lock and not letting the water circulate through the motor. I fixed it with J B Weld and it never ran hot again. Just thought you should know. No one should have to go through what I did.

Interesting and important comment, GuruRQ6V1 ..... and I have what may be a similar tale, involving a hidden small leak into the cooling system. I've battled the notorious overheating issues on a 2000 (Pontiac) Montana since we bought it new. We did everything you did, and more. (To the fine, if too generic advice above about "bleeding" or "burping" the system, that's fine -- if you don't have any fine leaks!) Moreover, the recurrent serious overheating in itself can cause many secondary issues -- including yes, headgasket failure.... Thought I was there, til recently, while changing out the EGR valve (and cleaning out those hidden, yet critical ports via the plennum), I managed to crack one of those notoriously fragile heater hose three way tees..... had a devil of a time fixing that rat's nest right! (Ignore the awful youtube videos out there on how (not) to replace that T plus all three of the hoses connecting thereto. Dawns on me that I might well have had a long term hair-line fissure in that brittle Tee. (There's two of them, btw), just enough to let air into the system..... and keep the over- heating roulette going. Alas, I still have some burnt wiring and cooling fan issues now to resolve, yet have reason to hope I may yet get another few years out of this family beast.