hotrodscrap

iTrader: (10)

If you didn't want to reprogram your PCM and wanted the fans to come on sooner(temp wise) could you use this?

http://www.summitracing.com/parts/JET-60602/

The car ('95 T/A project) has lived in the garage since I've had it and not driven much. I'm addressing years of neglect and don't really want to send off the PCM for tuning, as I am not keeping the car. I start and run it every other day or so to keep the battery charged because I'm working on interior and body stuff. I started it last night, and it ran all the way up to the red so I cut it off. The fans didn't come on either. I'm going to check relays for the fans, replace the pressure cap, and probably the stat while I'm there. What I'm wondering is, to check the fans for operation which pins on the relay block do I jumper to see if the fans turn? It is running in the garage while parked but still shouldn't run hot within a few minutes. I may have to invest in a radiator also, but I need to get the cooling problems solved no matter what. I'm just not trying to spend anymore money than I have to fixing something that isn't really broken, as it NEEDS attention and money elsewhere. Thanks!


-SS

ss.slp.ls1

iTrader: (36)

Just run 12v jumper and ground wires to each fan to see if they move. Then you'll know the fans are still good. Then you can swap relays around to see if that fixes it. You could use your horn or air pump relay to test it. Also might need to replace your temp sensor in the water pump.

JB_97ws6TA

iTrader: (6)

or of it ran up to the red and the fans didn't kick on you might need to change the temp sensor in the head and in fact the motor didn't get that hot but the gauge is malfunctioning (happened to me)

hotrodscrap

iTrader: (10)

Last night I replaced the temp sensor in the water pump, replaced the pressure cap, and used shbox's info to drain and refill. It took a long time to get hot but did (20 min). The fans still arent coming on, and I don't know which pins are 5 and 6 on the DLC as the instructions state. Also, the coolant is burping, boiling out of the Coolant recovery tank when the engine is revved. I need to take a picture of what I found though on the radiator, I think that some of the small hoses are running incorrectly. I won't be able to get pic's until this evening though. Thanks for reading.

-SS

ss.slp.ls1

iTrader: (36)

Ah hah...
Not the best pic:
http://shbox.com/1/low_coolant.jpg
The tiny hose on top, closest to the radiator cap goes to the coolant resevoir and the little hose right beneth it with the plastic braded sheth goes to the TB (or to the steam pipe if you did the TB bypass). If you have those two switch, you'll never build pressure and your coolant will boil out into the resevior. The same thing can happen with leaks in the system that bleed off pressure. Only thing is that the pressure loss shouldn't have any affect on your fans operating properly at the right temperatures. You do know that the fans do not come on until 226*/235* respectively right?

hotrodscrap

iTrader: (10)

So...... there is only one nipple there! Someone had broke off one of the nipples, and glassed over it. I'm going to have to get another rad. to fix the problem. Does anyone have a better picture of the nipples underneath the filler neck on the rad? I swear, this has got to be it! The car was a mechanics' lean car, that needed A LOT of work. Some pictures from that area, on a car of nearly the same years would help me out tremendously, thanks.

-SS

hotrodscrap

iTrader: (10)

ss.slp.ls1 you out there? Which pins do I jumper to check each fan for operation? It's jumpered under the dash at the diagnostic port right? I just tried it again, after about 20 min of garage running, I revved it a couple of times, coolant started puking from the recovery tank, temp went to RED ,and the fans never came on, wtf? Thanks again!

-SS

hotrodscrap

iTrader: (10)

Ok, just came in from the garage. I jumpered pins 5 & 6 in the DLC(diagnostic port) and the fans came to life, now what? As per http://www.shbox.com/1/4th_gen_tech2.html#radflush this indicated that the PCM is sending the correct signal for the fans, and the relays are functioning correctly, and also that the fan motors are good! So where is the problem? I replaced the WP temp. sensor, should I try throwing the head temp sensor in too? I just really want to get this figured out, help please....

-SS

hotrodscrap

iTrader: (10)

Bump for help!

-SS

the_merv

iTrader: (88)

Probably the PCM not sending the signal to turn them on.. my 1995 did it, a friend of mine's did it..another guy I know his car did it.

Do they turn on with the AC..they both should go on high.

May have to do Manual Switches..that is what I had to do.

1redta

HIJACK I still have my AC, but am having the same problem with the low speed fan. When you do the manual switch mod will it trick the ac compressor into coming on? as of now my ac won't kick on with the fans not working right.


BTW when I was messing around with the fans and associated wiring for the fans. I bumped the connector for the sensor in the head and they kicked on. all the posts lately say the one in the water pump controls the fans through the pcm and the one in the head is for the gauge? any thoughts

the_merv

iTrader: (88)

The one in the Head is strictly for the Gauges..unless someone re-wired something.

If you wire in the Manual Switches the way that I have done or SHBox's way(pretty much the same really when you understand the circuit) it won't mess with the AC at all.



I like that quote in your sig.. I've seen that in a few places.

LS6427

iTrader: (2)

If the head temp sensor has something to do with the fans....I'd definitely change that?

Sounds like you narrowed things down pretty well.

I'm no LT1 guy, so my knowledge of those are limited.


.

litch2004

iTrader: (1)

Mine did the same thing. Changed relays, both sensors, ran down all wiring, jumped the prongs and fans came on but would never turn on when they hit temp. I even went through 2 ecm's, still no dice. So i went with a homemade SLP style fan switch. i used a DTDP switch so i had one switch that controlled both fans. One way turned one on and the other way engaged both at the same time. I also tied in LED's so i could tell if they were working properly. Goodluck man it gets frustrating.

the_merv

iTrader: (88)

Yea it's definatley a pain when the Fans go out..
Head Sensor is for the Gauges.

litch2004

iTrader: (1)

+1 the one on the head doesnt even go to the computer. It is only for the gauge and will run if this one is not connected just fine.

hotrodscrap

iTrader: (10)

So what now, I don't want to have to run a manual switch and jimmy-rig it(not saying that man. switch is rigging it). I'd rather find out what's causing the fans not to work and remedy it! The temp sensor in the head is supposed to be for the gauge. I have replaced the WP temp. sensor though. The fans run when I jumper 5 & 6 pins too.

-SS

the_merv

iTrader: (88)

I have yet to see a repair for the PCM not sending the signal..my theory behind that is that the internals in the PCM wore out.

IMO a new PCM or installing Switches or another way to control them is the only option.

litch2004

iTrader: (1)

and like i said eirlier a new computer doesnt even work. I went through 2 and still no luck. GM couldnt figure it out either.

the_merv

iTrader: (88)

Manual Switches may be the way to go..