radiator fan

[phil_long]

I've noticed, througout this whole voltage issue i was chasing down, that the fan for the radiator draws the most current.  My SM shows 13.7-13.9 before that thing kicks on, then when it does, forget about it. anything i can do?

[Steve Wood]

As the SM is a lousy way to measure voltage loss, use your meter.  Check the voltage at the back of the alternator and at the fan connector.

Inspect the fan connector to make sure none of the contacts are burnt.

If the alternator is in good shape, there should not be much of a loss at the alternator when the fan kicks on.

[phil_long]

thats what i was thinking Steve. but ok.  I will inspect that.  I made some new grounds, got the ECM connectors straightened out, got the part from caspers that eliminate the bulb in the dash, and im still seeing varying low voltage.  but thanks

[Steve Wood]

as I said, the SM is not a good tool to troubleshoot  a voltage problem.  Check at the alternator to see if it is varying there.  If it is, it can be a tired alternator that needs an overhaul.

If it is steady and in the right range, then you can figure you have a connection problem elsewhere.

Sometimes, there is a high resistance problem in the cable between the alternator and the battery so check to see if the voltage at the battery is similar to what is coming off the back of the alternator.

If it is, check the ground side to the inner fender as well as to the turbo mounting bracket.

then positive side of battery to the starter.  Sometimes the connection at the starter is loose.

If that all is good, go to the ignition switch and check the connectors  there as shown on my site.  Also check the fuse block on the ecm-ign fuse to make sure there is no corrosion on the terminals in the fuse block.

[phil_long]

Yeah, i remember all the steps.  I checked the IGN, connector under the steering, etc. before i bought new harness for the ECM.  That voltage at the alt is a solid 14, and the battery is a solid 13.9.  im positive that the frame is ok because I just re-did the connection there. the turbo mounting bracket? didnt know a ground ran there.  I'll check it out.  and the pos to the starter.  got it

[Steve Wood]

There is no frame ground as from the factory.  The frame is not a direct ground as the car is built.

The ground cable should run to the lower bolt on the turbo bracket.  The small offshoot ground cable goes to the inner fender (the body is the main ground path for lights and such.  If there is no ground strap between the firewall and the engine, install one because the little one from the negative cable to the inner fender is pretty small.

[phil_long]

Ah, gotcha. Because i ran one from the grounds behind the passenger side head to the neg pos of the batt. But if one goes from the turbo bracket to the neg of batt, i jus did redudant work.......for nothing...

[ULYCYC]

Be careful with too many grounds.  You don't want to create a "ground loop" problem.  This will cause static in your radio and other more serious problems.
Simple ground form the neg batt cable to the turbo mount and fender as Steve said.  Also make sure the ones on the back of the head are clean and secure.

[phil_long]

Be careful with too many grounds.  You don't want to create a "ground loop" problem.  This will cause static in your radio and other more serious problems.
Simple ground form the neg batt cable to the turbo mount and fender as Steve said.  Also make sure the ones on the back of the head are clean and secure.

ok thanks!!

[Steve Wood]

Remember that the fan gets its power straight off the battery thru a relay.

If the fan has a good ground, the alternator should handle it without a bobble.  If the voltage at the alternator is still good when the fan is running, then we can probably discount a tired alternator and look for some resistance in the SM circuit which I described above.

If it makes you feel any better, one of my cars is showing a big drop on the SM while driving but I am seeing good voltage at the alternator.    SM is down about half a volt over what I am seeing elsewhere.

[phil_long]

Remember that the fan gets its power straight off the battery thru a relay.

If the fan has a good ground, the alternator should handle it without a bobble.  If the voltage at the alternator is still good when the fan is running, then we can probably discount a tired alternator and look for some resistance in the SM circuit which I described above.

If it makes you feel any better, one of my cars is showing a big drop on the SM while driving but I am seeing good voltage at the alternator.    SM is down about half a volt over what I am seeing elsewhere.

lol. My problem must be in the circuitry then. Im gonna focus on my other issues first. Back to my 10 page thread within a week. Lol