just picked up an '86 ta lb9, every thing is emaculate except for the fact the cooling fan stays on (when the key is in run position) and never seems to go off, not that this is a bad thing but could or should i just rigg my own on off switch or just let it run(isnt the computer supposed to handle this?), its anoying when the engines of and i'm just listening to the stereo
thanks

 

no, the computer does not handle this aspect. there is a fan switch mounted in the passenger side head between #6 and #8 spark plugs. check the wiring and insure that the wire (green I think) is still hooked up to the switch, sometimes when people have cooling problems they disconnect the switch and hook the green wire directly up to a ground which will make the fan run any time the key is on. if the wire is stil hooked up you may need to replace the switch.

 

Actually, on the LB9 (TPI) engines, the ECM does control the fan relay directly. The ECM will ground the fan relay operating coil based on input from the CTS and A/C pressure switch. The CTS in this case is located in the front coolant crossover in the intake manifold. The A/C pressure switch is located along the right subframe rail in the refrigerant lines from the condenser.

If the pressure switch is unplugged or has failed (or the wiring is damaged) the fan will operate constantly. If the CTS reports over 233°F, the fan will operate. If the dark green/white wire from the fan relay is inadvertently grounded, the fan will operate. Or, if the relay contacts are stuck (welded), the fan will operate.

 

wel for now, i don't think i have to worry about an over heat, BTW would this cause a CEL? i had one the other day and it went away after i revved the engine, could they be related?
thanks

 

DD,

They two might be related, or not. Incidentally, GM calls them "DTC"s (Diagnostic Trouble Codes). Your ECM should have stored the code for retrieval. Error codes are retained in RAM for the last 50 engine start/stop cycles. You should be able to do the paper clip thing and determine the cause of the code and lamp.

Does your's look a little like this?

 

DUDE, WHEN DID U GET A PIC OF MY CAR?
all except the ground fx are grey, does that have the grey interior too?

 

Hey, just to throw in my two cents, I wired my fans direct to a switch that is mounted under the dash, and I find it so much nicer to be able to turn them on whenever, if the car is on or not. It really is a better deal as far as I'm concerned, just as long as you dont forget about turning them on. I think it may also save on the fan motor's life, with being able to shut them off once you're going over 25, because after that it just seems as though they're doing more harm than good.

 

well go figure, while driving to get the car registered, the t/a overheated/boiled over thrue the cap on the expantion cap. its still hot know so i didnt bother with seeing if the hoses collapsed or anything. it seemed that the car got hotter while moving but temps didnt drop while at the red lights. i had the heat on and that didint seem to help (TG i have t-tops!) on the end of a ten mile trip, temps went rite to the red line on the guage. i'm wondering if the rad cap is just letting pressure blead into the expantion tank too early for the functions of pressure to keep the temps down, i'm going to check for an air dam and try to use the cap off of my '79.
in the mean time, i mite as well check to see if water's circulating.