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> Can't get rear heater fan to come on, Even in AZ we need heat sometimes.
3d914
post Jan 2 2004, 02:15 PM
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I've been assembling all the parts to re-install heat in my teener, and now I'm down to checking out all the wiring. But I'm not getting any power to the rear heater fan (in engine bay).

I've cleaned up the connectors and wiring from the heater switch behind the shifter (ground side of the circuit). It comes out at pin #9 on the forward 14-pin connector on the relay board.

Power should be going to pin #11 of the same connector, but Im gettin zip.
This #11 connects to pin #10 of the lower-right 12-pin connector on the relay board - which bridges to pin #11 - then over to #87 of the relay.

I'm getting power at #30 on the relay - but don't have a way to check where its going from there. The relay is new, and I've swapped with others - but keep ending up with no power.

Any ideas - what I might be missing?

TIA,
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Bleyseng
post Jan 2 2004, 02:23 PM
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Check the fuses at the relay board not the fuse box. Usually its the relay in the relay board that goes bad.

Could be the fan is toast? check with 12v from the battery.

Geoff
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Brad Roberts
post Jan 2 2004, 02:58 PM
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Fuse or fan. Sounds like you are close.

B
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rhodyguy
post Jan 2 2004, 03:09 PM
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you are sure that the green(i believe) wire is connected to the bottom if the heater lever on the console? and that the lever is pulled all the way up?

kevin
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3d914
post Jan 2 2004, 03:26 PM
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Guys,

Yes I have checked the fuses, the fan, and the green/red wire from the heater switch. I have near-zero impedence from the switch to the #9 pin on the relay board connector.

I've swapped relays, but get the same thing - no power at pin #11 of 12-pin relay connector.

Can I do anything with the relay that would enable to see if its bridging between #87 & #30?

Or could I pull the relay and jumper #87 & #30 to see if the circuit is at least functional?

Thanks,
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Brad Roberts
post Jan 2 2004, 03:29 PM
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This where I use a relay that I have pulled the cover off of (or us the jumper wire like you suggested).

Sorry for the fuse reference.. you didnt say whether it was good or not or whether you had cleaned the contacts for it.


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3d914
post Jan 2 2004, 03:33 PM
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Brad,

No sweat.

Just as a mental check - am I correct that the #85 & #86 of the relay carries the ground side of the circuit, and #30 & #87 carries the + side?

Thanks again,
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Brad Roberts
post Jan 2 2004, 03:38 PM
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You are correct. 30 and 87 always have the power.

What engine harness do you have in the car ?? The late ones have a small green jumper wire in them and the early ones dont. The harness that attaches at the back of the relay board.

I need to leave and I wont be back on until late tonight.

B
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3d914
post Jan 2 2004, 03:42 PM
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Brad,

I have a late one - and it does have the small jumper wire from pin #10 to #11.
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Gint
post Jan 2 2004, 03:57 PM
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Could be the heater motor.


I attempted to rebuild a heater blower motor without much success. Mechanically it was shot. You can see in the pictures that the choke coil from the power lead to the brush kept de-soldering itself when the windings smack the magnets due to the shoddy bushing in the bottom of the housing. Notice the grooves in the magnets.

Check out this link
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boxstr
post Jan 2 2004, 05:01 PM
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Recheck the wire connectors in the plastic block for the two wires from the loom to the heater motor. Pull on them and recheck.
Also turn the key on and make sure you have the levers on the dash in the correct position.
CCLINPTDT
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3d914
post Jan 2 2004, 05:29 PM
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OK here's what the problem is: the red heater lever (behind the shifter) is not grounding properly.

I pulled it out. It has a plastic arm with the green/white lead connected to a small bead on the opposite side. When the lever is pulled back (up) - this bead connects with the metal arm of the lever.

However, there is nothing that appears to ground the metal arm of the lever to complete the circuit to ground. The metal arm is shielded from the bracket that mounts the whole thing to the body - and would ground it.

Is there something missing? (IMG:style_emoticons/default/icon14.gif)

TIA,
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rhodyguy
post Jan 2 2004, 07:13 PM
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put one lead of your multimeter on the tab the wire goes on and the other lead to clean metal on the center tunnel.with the lever fully pulled up you should have 0 ohms resistance. 0 conductivity with it pushed down. this circuit is pretty easy to follow in the haynes manual. the key does have to be on for the fan to run.

kevin
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SirAndy
post Jan 2 2004, 07:22 PM
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it grounds to the chassis through the 2 bolts that are used to bold it down.

if you have the lever out and away from the tunnel, it won't ground ...

try grounding the green wire directly to the chassis and see if the blower runs.
key needs to be ON (IMG:style_emoticons/default/wink.gif)

Andy
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3d914
post Jan 2 2004, 11:46 PM
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Thanks guys,

This varifies what I suspected. Some genious must have taken this one apart and re-assembled it so that the lever is shielded from the bracket and now does not ground like its supposed to.

I'll have to take it apart and see what can be done.

Thanks again.
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3d914
post Jan 4 2004, 05:11 PM
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NEWS FLASH !!!! NEWS FLASH !!!!

I did some further investigating with the heater lever and I have my final report.

The lever portion is fully isolated from the plastic arm AND from the mounting bracket that bolts it to the floor.

The grounding connection is applied to the lever via the bead on the plastic arm. From there the arm is grounded via the .... are you ready for this? ... via the METAL CABLES that connects to the heater boxes.

DUHHHH! (IMG:style_emoticons/default/huh.gif) This is one place where I think Porsche really fell down on the design side. Unless someone can come to Porsches defense - I just don't get this one!

Anyway - its one for the books - scrap books that is!

Enjoy!
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rhodyguy
post Jan 4 2004, 06:11 PM
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does that mean the fan now runs?

kevin
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3d914
post Jan 4 2004, 09:41 PM
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Kevin,

Yes, it will when I get it installed. Still just checking everything out first. Didn't want to have to go chasing bad connections AFTER I had everything installed.

Thanks again,
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Brad Roberts
post Jan 5 2004, 01:58 AM
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Hum. Something doesnt sound right. I knew that it had isolaters on it.. but I have used that switch for years to turn on the ground for the fuel pump relay (theft deterant).. with no heater cables or fan in place.

B
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3d914
post Jan 5 2004, 12:46 PM
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Brad,

You may be one of those who have a lever that happens to touch the mounting bracket when up - which then could close the ground circuit.

THe two that I tested - One touched & the other didn't, but neither one completed the ground circuit.

I'm just shootin in the dark here with testing as I have not found any hard data on how this is supposed to work. Somebody straighten me out here.

PS: I like your anti-theft device! Have you ever bumped it while driving?
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