electric fan problem

[Lt1_8U]

okay, so today my car overheated and i found out that i was leaking coolant. I found out that the leak was coming from the upper hose on the radiator side. i got new clamps and a new hose but it still leaks. I let it cool down awhile and i started it and laid underneath it, it was fine for like 5 minutes but then the temp rose up and it started leaking. my fans never came on:evil: the hose only leaks when it hits a little before the red line which is 260 i believe.

anyone know why my fans would not turn on?

[BonzoHansen]

what car?

[Lt1_8U]

oh sorry lol, my 96 trans am

[BonzoHansen]

is it all factory, no modifications?

[Lt1_8U]

it has a slp intake, and a borla cat-back.

[BonzoHansen]

lol I meant mods to the fan, so no. Good.

Lemme find the fan diagrams, not sure if that car has 2 or 3 relays. IIRC the ECM turns the fans on. Did you check fuses? Did you try turning on the AC and see if the fans kick on?

[Lt1_8U]

lol I meant mods to the fan, so no. Good.

Lemme find the fan diagrams, not sure if that car has 2 or 3 relays. IIRC the ECM turns the fans on. Did you check fuses? Did you try turning on the AC and see if the fans kick on?

i changed one fuse
and that didnt do it. i will go out and change the others now, if that doesnt do it i'll turn the A/C on. i'll post back in a little bit

[Lt1_8U]

i tried it again, the fans didnt turn on when i put the A/C on and i changed the fuses and still nothing. on the inside of the fuse box in the engine bay it says which relays are the cooling fans, there are 3. tomorrow i guess i will buy 3 relays?

[SRGN]

See if you have power/ground at the fan when it's supposed to be on before you start throwing parts at it.

[sweetbmxrider]

yeah if your temp gauge on the cluster is above half, your fans deff should be on. you could try jumping it with a power lead from the battery or switching it with a known working relay. this could be many different things so please don't chuck parts at it, for the sake of your wallet!!!!

[Lt1_8U]

i just woke up now so i'll check the power and ground and i will post whats going on....thanks a lot guys

[Pampered-Z]

Be very careful trying to jump the fans! They are turned on by the ECM grounding the circuit! If you add power or feed power back into the grounded side you can fry parts, even the ECM!

There is also a way to ground the relays (manual fan switch mod), but I'm not 100% sure on the 96-97 wiring as its different them my 93. So I can't tell you the proper way.

The two fans work independent. Fan1 (primary) comes on at 221 degrees, fan 2 @ 235 degrees. Both fans are controlled thru the ECM. I think on the 96-97s each fan has its own relay, I believe the 3rd is the AC fan on relay.

The most common type of failure is with the sensor that gives the temp to the ECM. It is located in the front of the water pump housing on the right side down below the small inlet (It is a bit of a PITA to get to.). The dash gauge is operated off a completely different circuit and by the sensor in the driver's side head. So the reading on your dash does not mean the ECM has the same temp reading, since neither fan is working its most likely not a relay, I'd lean more towards the sensor.

Couple things you can try before buying parts:

1) There should be two fuses and relays in the box under the hood. The relay for the fog lamps is the same as the fans, try swapping that, see if the lights still work, or a fan comes on.

2) The ECM uses the coolant temp for fuel tables. If you noticed the car is running very rich, that might be another reason to look at the sensor as to why you're having this issue.

All else fails, have someone with a scanner see if the ECM coolant temp matches or at least is close to what the gauge on your dash is reading.

3) Never tried this myself on an OBDII car? So maybe someone else with a 96-97 could do it and verify it works??? With the key on, but the engine not running jump the #5+6 pins on the ADL, this should put the ECM is FTM ( Field test mode - form of Limp Home Mode), causing the check engine light to come on and the fans should come on. If the fans do come on, it's probably the sensor. If they don't them you may have a bigger issue. Time to break out a volt meter and testing wires from the ECM to the relays.

[Lt1_8U]

Be very careful trying to jump the fans! They are turned on by the ECM grounding the circuit! If you add power or feed power back into the grounded side you can fry parts, even the ECM!

There is also a way to ground the relays (manual fan switch mod), but I'm not 100% sure on the 96-97 wiring as its different them my 93. So I can't tell you the proper way.

The two fans work independent. Fan1 (primary) comes on at 221 degrees, fan 2 @ 235 degrees. Both fans are controlled thru the ECM. I think on the 96-97s each fan has its own relay, I believe the 3rd is the AC fan on relay.

The most common type of failure is with the sensor that gives the temp to the ECM. It is located in the front of the water pump housing on the right side down below the small inlet (It is a bit of a PITA to get to.). The dash gauge is operated off a completely different circuit and by the sensor in the driver's side head. So the reading on your dash does not mean the ECM has the same temp reading, since neither fan is working its most likely not a relay, I'd lean more towards the sensor.

Couple things you can try before buying parts:

1) There should be two fuses and relays in the box under the hood. The relay for the fog lamps is the same as the fans, try swapping that, see if the lights still work, or a fan comes on.

2) The ECM uses the coolant temp for fuel tables. If you noticed the car is running very rich, that might be another reason to look at the sensor as to why you're having this issue.

All else fails, have someone with a scanner see if the ECM coolant temp matches or at least is close to what the gauge on your dash is reading.

3) Never tried this myself on an OBDII car? So maybe someone else with a 96-97 could do it and verify it works??? With the key on, but the engine not running jump the #5+6 pins on the ADL, this should put the ECM is FTM ( Field test mode - form of Limp Home Mode), causing the check engine light to come on and the fans should come on. If the fans do come on, it's probably the sensor. If they don't them you may have a bigger issue. Time to break out a volt meter and testing wires from the ECM to the relays.


thank you for the info! lol. i changed the fuses and i switched relays and still nothing. The A/C fan wont even turn on. i guess the next thing would be to get a new sensor.

[sweetbmxrider]

yeah pampered is right. i don't know why i said jump i meant test light to battery. if they don't work with a/c its not going to be the coolant sensor. turning the ac on is basically a switch to turn a fan on. if you have a test light, i would check to see if you are getting power at the fuses and the fan with ac on.

[Lt1_8U]

yeah pampered is right. i don't know why i said jump i meant test light to battery. if they don't work with a/c its not going to be the coolant sensor. turning the ac on is basically a switch to turn a fan on. if you have a test light, i would check to see if you are getting power at the fuses and the fan with ac on.

i just checked them, im getting power at the fuses but then when i check the wires, i have no power... and yes i checked my ground to the test light

i also found a little black box....
http://i183.photobucket.com/albums/x94/69novaguy/1230081844.jpg

it branches off of the wires from the fuse and relay box. its pretty flat and one the one side it say GUIDE What the hell is it! haha

[sweetbmxrider]

you had ac on when you checked the fan?

[Lt1_8U]

you had ac on when you checked the fan?

yepp

[BonzoHansen]

I'm striking out finding proper 96 V8 firebird wiring diagrams for the fan circuits. These are from the AutoZone site. It looks like a standard relay pinout. If so, I'd guess this….

With the key in 'run' for each fan:

Assuming 5&2 is the trigger circuit, one of 5&2 should be the ECM lead (ECM supplies ground when required), with the other being hot. Test for hot. You should be able to ground the trigger (ECM) side down to trigger the relay.

Assuming 1&4 is the power circuit, one should be hot and the other goes to the fan. You could jump this circuit to start the fan. These wires will be bigger gauge than the trigger circuits.

Any lt1 guys verify this?

http://econtent.autozone.com:24991/znetrgs/repair_guide_content/en_us/images//0900c152/80/0b/87/fb//large/0900c152800b87fb.gif

This shows the trigger leads from the ECM as dark green and dark blue
http://econtent.autozone.com:24991/znetrgs/repair_guide_content/en_us/images//0900c152/80/0b/88/2b//large/0900c152800b882b.gif

If you have power at the relays and the relays are good and the fans turn on, your issue is ECM related (ECM, wires, sensors).



Best fan diagram I can find is 99 5.7L. ECM colors look to be the same:
http://econtent.autozone.com:24991/znetrgs/repair_guide_content/en_us/images//0900c152/80/09/fe/3b//large/0900c1528009fe3b.gif

[deadtrend1]

i just checked them, im getting power at the fuses but then when i check the wires, i have no power... and yes i checked my ground to the test light

i also found a little black box....
http://i183.photobucket.com/albums/x94/69novaguy/1230081844.jpg

it branches off of the wires from the fuse and relay box. its pretty flat and one the one side it say GUIDE What the hell is it! haha

that is a relay (or something like that0 for the pop up headlight motors

[Anti_Rice_Guy]

yeah if your temp gauge on the cluster is above half, your fans deff should be on.

Ours never did, and always went way up in traffic. IIRC, stock fans come on @ 210 or 220. No issues here since the 160 thermo + Hypertech tuned for fans to come on at 180.

[Lt1_8U]

well i got my fans to work but heres a major problem.

my cars runs like crap, when i start it up i have to give it gas and then its very rough. eventually it smooths out but it still is running weird. the temp goes up very quickly and gets to the red line limit(even with the fan on) What doesnt make sense is i put the heat on when its supposedly 210 and it blows cold air:-x wtf if up with my car!?

I might just take it to a place if no one knows whats going on

[BonzoHansen]

did it run like crap prior to you getting the fans to work? how did you do that?

You sure you have a filled coolant system?

[sweetbmxrider]

air pocket in the cooling system? try bleeding it? don't think it would make it run rough. coolant is topped off right? how does the oil look?

[Lt1_8U]

i grounded the wire off of the fan sensor on the water pump, it ran like crap so took off the grounded wire. still ran like crap but my fans stayed on without it being grounded.


system is full but i have a leak now in the rad so i need to buy a new one.

engine oil is full, although it needs to be changed

[Lt1_8U]

could it be my sensor thats throwing my car off and making it run like crap?

[BonzoHansen]

maybe. engine light on?

[Lt1_8U]

yes but its always been on, someone said , see if my t-stat is bad

[sweetbmxrider]

could be, i would check for new codes in the computer. water pump might not even be working. could be clogged somewhere. try comparing the upper and lower rad hose temps by hand i guess.

[Lt1_8U]

okay, so today i went outside and my car started right up without a problem.. i drove it up my street and its running funny, its cutting out and it doesnt seem like it has much power. my fans are on all the time but the temp climbs up to the limit very quickly and even when it says around 210 + the air from the vent is cold

[SRGN]

air pocket in the cooling system?

That's where I would start as well. Bleed the cooling system, an air pocket will cause the exact symptoms you describe.

[Lt1_8U]

okay, i will do that tomorrow.

thanks a lot guys for the constant help with this problem:mrgreen:

i'll keep you updated with what goes on

[Lt1_8U]

how would i get the air out of the system? someone said i need to (burp) the system. while its running i need to have it at like 3 grand and squeeze the upper coolant hose then someone has to open a vent on the engine?

can some please explain how to do this.

thanks

~jim

[sweetbmxrider]

i'm sure someone can pull a diagram. there are two air bleeders on the lt1 hoses. it looks similar to a brake bleeder. you crack them open and let the car run. you will see it spitting a little coolant out because air is coming out too. once it is a steady stream of coolant, shut the bleeder. it may take a couple tries, you could have bigger problems though.

you don't need to do all that nonsense, though it may work it isn't the "by the book" way.