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Discussion Starter · #1 ·
Up until a while ago, the blower in my car would work sometimes and other times not. The relays and resistors check out ok, and all the wiring is hooked up with the exception of a mysterious cut purple & black striped wire that runs to a secondary switch (not the main one)on the control unit. If I remember right, it joins in with a brown one and the other end connects somewhere in the fuse block. It might've been a fusible link because when i found it, the insulation was all melted so I cut it out which probably wasn't too smart.
Another problem I had was, one terminal on the plastic plug for the main switch would get real hot and start burning the plastic in the plug. A terminal under the hood on the relay did the same thing; they might be connected somehow. The blower motor squeals, but still turns, do you think replacing that would solve all the problems?

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1970 Chevy Custom El Camino
Originally was & will be Green Mist & Silver w/Green Vinyl Top (now black)
350ci/300HP 4bbl & Dual Exhaust
TH-350 - 2.73 Posi Rear - Factory PS, PDB, PW, Tilt, A/C & More
My El Camino Home Page
Other Restorations -1969 Snowco Trailer & 1967 Sears Custom 600 Tractor
Team Chevelle Member #995
 

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Maybe. The brown wire is the 12 volt feed line for the low speed functions. Low speed also goes through the relay. Interesting that the fuse, for the high speed position never blew once in awhile (under the hood). The fan motor is dying. Changing it won't be a waste of money.
 

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Most anytime you find signs of heat at a connection point, it is caused by a poor connection at or very near that point
Also a poor connection could be the cause of intermittent motor operation

Like John said, If the motor is making a noise it's time to go get a new replacement motor
They aren't that expensive at either O'reilleys, Auto Zone or Advance Auto parts
 

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Just my $.02. Shawn, Heat at any connection point is usally caused by high amperage (Bad bearings in the fan would cause this). I would also check to make sure that someone has not installed a larger fuse in place of a correct one to stop it from blowing. John is right the fuse should have blown.
 

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Discussion Starter · #5 ·
I checked the fuse under the dash, and the metal thing inside was wavy but not broken. The terminals look like they have a little surface rust too. I checked out the motor (bypassed wiring and hooked it up to a hot lead)and it still turns but makes noise. I still have to pull the fender yet to get to it though.
I know it's all getting power in on the orange lead that goes from the horn relay to the system, but from there it stops. Ground should be ok too. The switch isn't getting anything and I tried replacing the relays under the hood (I thought that was the problem)but it didn't make any difference. Is the control unit supposed to be grounded? Do you think something might've happened behind the fuse panel? All the other wiring is intact that I can see.

EDIT: Actually, with my harness, there is just a spliced wire running from the relay to the orange lead for the system, no fuse there. Since the plugs melted and the contacts look a little dirty, I'll probably just get a new one. How do the new repro harnesses compare to the used ones? Do they match?

[This message has been edited by Shawn (edited 01-15-2002).]
 

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The orange lead that's under the hood is power for the fan in the high position only. That line should be fused. The brown lead comes from the fuse block. It is on another fuse. This runs the lower speeds. There is no fusible link in the brown lead.
What would I do:
Replace the motor
Add an in-line fuse in the orange lead.
Clean or patch up all connections and wires.
Replace the wavey fuse.
See what happens after you clean it up. Post back and then describe what it is not doing, such as doesn't run on low speeds. After it's all working then decide on a new harness. I hate to see you troubleshoot with a brand new harness and smoke it. They do cost money.
Just my opinion.
 

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Shawn

As stated last time you asked about your blower motor. The “orange wire from the horn relay” ONLY supplies power to the blower when high speed is selected and it should have an inline fuse <BLOCKQUOTE>quote:</font><HR> the power for the blower harness comes from an orange wire, right? On the end of it there's a strange round metal thing, maybe for a fuse I'm not sure. I spliced another wire on the end of it and ran that to the horn relay <HR></BLOCKQUOTE> This statement leads me to believe you don’t have an inline fuse. If not this can be part of the reason you are burning insulation. The Purple/Black wire may be the power supply to the TCS. The 70 SS gauge harness has the TCS powered from the brown heat A/C master switch connector. You need to replace the blower motor and troubleshoot the blower circuit as follows. Check all connection for burned or loose terminals.

As posted on 12/28/01

There are two sources of power to the blower. The orange that you spliced and connected to the horn relay is the supply for the high-speed only. You should have an inline fuse 30 amp for this source.
Use a voltmeter or a test light to check the other source. Start at the fuse block, the top right 25 amp fuse is for the heat A/C. With the ignition on you should have voltage on both sides. At the control assembly check for voltage at the master switch. The brown wire comes from the fuse block. The other terminal has a tan and light green with the control lever in any position, except off you should have voltage here. At the blower speed switch the tan wire comes from the master switch you should have voltage here. Place the fan switch to low speed you should have voltage on the yellow wire, medium 1 puts voltage on the light green wire, medium 2 puts voltage on the light blue wire and high puts voltage on the #18 dark blue wire. At the step resistor pull the connector plug check for voltage on the yellow (low), on the light green (med. 1) and on the light blue (med. 2). From the step resistor the #12 dark blue wire will be spliced to a #12 purple wire (it may have a stripe). The purple wire connects to the blower. This completes the circuit for the lower speeds. At the blower high speed relay, with high selected you should have voltage on the #18 dark blue wire. This picks up the relay connecting the #12 orange to the #12 purple, which connects to the blower completing the high-speed circuit.

Actually no blower circuit is complete if you don’t have the blower motor grounded. A #12 black wire is connected to a spade lug at a blower mounting screw. This black wire is grounded to the firewall above the high-speed relay. The high-speed relay will also needs to be grounded a #16 black wire is spliced to the #12 blower ground wire. Make sure all ground connections are clean and making good contact.
 

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Discussion Starter · #8 ·
Thanks John & Elree, I'll give it a try tomorrow and see how it goes. I'll pick up some new fuses and a voltage tester and see what happens. You're probably right about it being the connections, that's the only thing it really could be, I'll clean off the terminals and test it out. What do you recommend for cleaning the terminals? What tool could fit in there to clean em off?
BTW, you were right, purple wire was for TCS, I noticed the same one under the hood by the wire gutter. It isn't hooked up anyway.
 

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If you are not dropping the switch, the best you can do is use some very fine sandpaper. 400 or higher.
 

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The female spade terminal can be removed from the plastic connector plug. One side of the terminal has a tab that holds it in the plug, use a small screwdriver to bend the tab this will release the terminal. You can clean it with a fine wire brush. Bend the tab back out so that it will latch when reinserted.


 

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Discussion Starter · #11 ·
Did all that, and now all the speeds work except for the highest one. The connection still gets hot, so I plan on replacing the motor. In the meanwhile, I have to try and figure out what the higest speed doesn't work.
 

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Great news, you actually fixed some of the harder stuff. Did you check out the orange wire under the hood for the 12 volts it's supposed to have?
 

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Check the connections on the back of the switch for power as you change the position. My switch was corroded on the inside, and I had to take it apart and clean it up in order to get blower on all speeds.

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Cecil Hawkins
San Diego, CA
1971 GMC Sprint
The Project
All I need is time...and some $$$
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