car

[brock]

Hey, smart xs'ers. Here's an electrical question relating to my neighbor's car. If I can fix his old dodge, I figure it earns me refrigerator priveleges (and he drinks the expensive beers).

His cooling fan went out. instead of tracking down a short or replacing a relay, I said, let's just by-pass it. I cut the wire, jumped it to the battery, and voila, the fan came back to life. I thought, well, I'll just hook it to the alternator, it'll come on when the car is running, turn off when the car is not running, and no one will ever have to worry about it again. I hooked it to the alternator, but even with the car off, the fan started right up. Shouldn't the alternator only put out power when the belt is turning it? i don't know.

Anyway, where should I run this jumper wire to the fan so that it only runs when the car is running?

Thanks guys. And remember, successful electrical work keeps a fellow xs'er in expensive beers, at least through the summer.

Bobby

[BLUEJEEPLAB]

First, a word of warning, wiring a fan to run all the time will cause the fan motor to burn out much sooner. Second, it will affect the way the sensors on the car work because the engine will not always reach optimum temperature, particularily in the winter.

That being said, I would look to splice into an accessory line, such as the AC controls (if the fan is problematic, then more than likely, AC is old enough to not work either). I'd avoid ignition circuits for the same reason you try to avoid drawing down the voltage on an XS, the igntion will fail to work if the voltage draw gets too great and you fall below a set voltage.

The fan is running all the time because the alternator is connected to the battery to charge it. Fiund a switched circuit.

[mro]

cooling fan

Don't know how long the electric fan will last before you burn it out if you wire it direct.

Fan only runs when needed and is not needed all the time, like above 30 MPH. A thermostat regulates fan which may be bad and why it's not working.


mro

[BLUEJEEPLAB]

Okay, just noticed you are in Florida (lucky B@#^%$*), ignore the comment about proper temperature in the winter (although it does hit freezing in T'hassee, right?).

[mro]

Hi ya BLUEJEEPLAB

What you said

Can freeze all the way down to Miami too

Been there, done that



mro

[motoman]

Hey there Brock, not sure what flavor vehicle your on, but there is a electic sensor screwed in radiator tank. replacing that should solve your problem. There may be more than one(other would regulate timing advance according to engine temp.) Follow out wires as to which temp sensor goes to fan. Had same problem on girlfriends 91 Voyager, and just wired it to a wire in loom under hood that was ignition hot with key on. Has been working like this for over two years now with no problems and temp gauge stays constant when at operating temp.

[prometheus578]

"I'm a big fan of yours!"

Yeah, there should be a temp. sensor on the block that tells the fan when to turn on. (My fans are always turned on, but then again, my fans adore me)
Should the fan be on all the time? Had to hotwire the fan on my Camaro when the sensor failed, ran it like that for years. Ex wife's hubby, who is rather "mechanically declined", dicked with my son's starter and messed up the sensor wire somewhere, so I hot wired him, too. (Son's car, not the ex's hubby).
((To not have the fan running all the time, I would wire it to the wiper switch. When the engine gets too hot, anti freeze starts to boil and the steam and antifreeze spray will then get on your windshield to let you know you're too hot. Turning on the wipers not only cleans the windshield again, but also turns on the fan to cool down the engine. sort of "...two birds with one stone, thing"))
Find the temperature sensor for the fan and replace it, provided the wires are not the culpret.

[prometheus578]

"More fan mail..."

but there is a electic sensor screwed in radiator tank

Mine was a sensor on the block.

[webbcraft2150]

Park the freakin car and buy a XS11. Problem solved.

[trbig]

There should also be something from the A/C system. When you turn on the A/C, that fan should come on. I know a replacement fan can be over 100 bucks aftermarket, but it does sound like just a sensor out... no idea on a price for that. I would check that before I started using that "Southern Inginuity" on it.

Tod

[Jerry]

When I bought my '92 Saturn, fan would not come on. Through user group information I traced it to a bad coolant sensor in the block. Replaced sensor, fan comes on at right temp and no problems. Same sensor feeds info to the FI system as part of the enrichment system.

I'ld take the time to fix it right. Sensor was around $13.00, not worth 'custom" wiring and problems it might bring, and it is likely the same sensor is causing trouble elsewhere.

Do a web search for the brand/model and try to find a user group; a lot of tech info (just like XS11.com!) floats around and the fan issue has probably been addressed.

Any other Saturn owners, check out www.saturnfans.com

[80mdnt11]

Fix It / Or Modify?

Brock,
Two ways to check cooling fan-------1) Turn a/c on, fan should come on 2) Hot wire ( i.e. youv'e done that)
Prob. most likely cooling sensor on block located around thermostat area. If you choose to modify, under dash at fuse block find acc. term. You can run wire off that to toggle switch, from toggle switch to fan--------- Then, IF operator is AWARE of their vehical, run fan as needed!
JMO, Been there----------done that!!!!!!! Jack of all, Master of none!!!!!!!!! Oh well, just think of all the experience

[BLUEJEEPLAB]

JMO, Been there----------done that!!!!!!! Jack of all, Master of none!!!!!!!!!

Huhhuhh huhhuhhuhh, huh, he said ... Jack.

Sorry, feeling infantile and missing good ole B and B. Have to go home and watch the tapes tonight I guess.

[Radiation]

Me too

My daughter had the same prob with her car. I finally went to NAPA and bought a fan kit. It is a unit that you mount under the hood.It has a temp probe that you install in the radiator hose and it splices in to any hot wire. You just turn the knob on it to come on at the temp that you pick. About $40. Money well spent!

[ccogswel]

It would really help to know what year the Dodge is. You say old so I'm guessing early 80's to early 90's. I know. A lot of years there. Some are right about the temp switch being in the radiator or by the temp housing. The problem is some Dodge's had both. More then likely the switch on the radiator is bad. You can pull the plug and make a jumper wire and let the plug lay down away from the fan. This worked on my moms old 84 Newyorker. Or if you really want to you can wire the fan to the hot wire on the coil. Just find which one is the ground. It's not good to do it this way but it can be done as a temp fix. The switch for it isn't that high. If you neighbor goes to replace it be carefull as you have antifreeze to deal with. No mater which temp switch you replace. Also the reason why the wire on the alternator ran the fan when the car is shut off is the alternator needs a hot wire all the time to make it work. That is why they say disconnect the battery when replacing the alternator as that wire is hot at all times. Most cars are like this. That is also one way you can hotwire an old car. Just run a jumper wire from the alt to the hot side of coil and short out the starter and your off. No radio of signals but the brakes lights work as with the headlights. And it's best to do it with a car that the steering wheel doesn't lock. Don't ask me how I know this
Hope this was some help. After all I love MOPARS!