1972 Riv Wiring Help for Blower

Discussion in 'The Big Chill' started by Daves72, Jul 20, 2015.

  1. Daves72

    Daves72 I get jokes.

    Hey Guys I can't put my hands on my manual since I moved, it's in a box around here somewhere.

    I'm only getting medium 1 and medium 2 but no low speed or high speed on the blower. This car has the manual temp control.

    Here's what I found while testing.

    Blower motor resistor:
    Term 1: orange wire to blower relay
    Term 1 to 2: 0.4 Ohms (medium 2 - black w/ blue stripe)
    Term 1 to 3: 1.0 Ohms (medium 1 - tan wire)
    Term 1 to 4: 2.4 Ohms (low - brown wire)

    Blower motor relay:
    3 post connector: (Orange wire from resistor, medium gauge black wire with orange stripe to fan, and heavy gauge blackish(?) wire with constant 12 volts any time the battery is connected)

    2 post connector: (Small gauge black wire and small gauge black with orange stripe)
    I could not figure out what the black wire goes to, no continuity to ground or positive on battery. The small gauge black with orange stripe from fan switch.

    Switch:
    Switch in low = 12v on brown wire to resistor
    Switch in med 1 = 12v on tan wire to resistor
    Switch in med 2 = 12v on black w/ blue stripe wire to resistor
    Switch in high = 12v on small gauge black w/ orange stripe wire that goes to relay

    I bypassed the relay altogether to test the low, med1, and med2 speeds but still did not get a low speed fan, only med1 and med2.

    With the battery disconnected to avoid arcing, I jumpered the heavy gauge constant 12v wire to the blower wire (medium gauge black w/ orange stripe). Upon reconnecting the battery I got high speed blower.

    Some photos:
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    Also, what's this on the fire wall? It has two brown wires and one black lead that's not connected but I think it's supposed to connect to a ground terminal at the block to firewall ground strap.

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    Thanks!
     
  2. Briz

    Briz Founders Club Member

    Ive found that most of the time when your blower has a issue like this its the resistor.
     
  3. Daves72

    Daves72 I get jokes.

    I went searching and found my manual. It looks like the ground for the relay is supposed to be on the A/C with the compressor clutch ground, and my ground isn't connected at the bracket.

    It also looks like the device on the firewall in the photo above is the Temperature Delay Relay and is normally closed. Apparently I don't have the Engine Thermo Switch on the back of the passenger side head. I think this controls the low blower even when the selector is in the off position. Does anyone have a part number for that?

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  4. Daves72

    Daves72 I get jokes.

    Thermo Switch - AC Part 6489285 or 6490265

    Here's a better look at the connector that goes to the blower delay relay. It looks like mine would use 6490265.

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  5. Daves72

    Daves72 I get jokes.

    I reconnected the ground at the A/C bracket and that solved High, Med2, and Med1 but I still didn't have low. There was a moment when I had High and Med1 only but I isolated that to some corrosion on the blower resistor terminals. A quick buzz with a wire brush in my Dremel solved the missing Med2 speed. So, I then focused my efforts on the temp delay relay.

    I found that it is pretty rusty. I imagine this is because it's right under the heater hoses on the firewall and any hose leak would have dumped coolant all over it. The connectors were seized on with rust and I used some WD-40 to loosen the bond and was able to work them off with a flat blade screw driver. Then, I jumpered the brown connectors together and, lo and behold, I had a low speed fan. Sweet! Apparently the corrosion was not allowing enough current through even though I was reading 12 volts on the brown wire.

    I tested the temp delay relay but it's seized internally. Yesterday I bought a Thermo switch on eBay and now I'm going to see if I can find a replacement temp delay relay, part #3961573.

    Here are some photos after I cleaned the terminals with my Dremel.

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  6. flynbuick

    flynbuick Guest

  7. Daves72

    Daves72 I get jokes.

  8. Daves72

    Daves72 I get jokes.

    Received in email this afternoon:

    "Hello David,

    Thank you for ordering parts with us.
    We are writing to inform you that order M******* has been voided. Your order has been voided because of the following reason(s): The ordered part(s) have been discontinued (no longer available) and/or is backordered with no ETA date by the manufacture.

    If you have further questions, contact us.

    Regards,
    Customer Service
    Gmpartseast.com"

    Soooo much for that! I'll keep checking other places because I'd like to avoid paying $50 for a relay.
     
  9. Daves72

    Daves72 I get jokes.

    I found one a little cheaper ($43 including shipping) on eBay. Not ideal but I guess I have to take what I can get.
     
  10. DeeVeeEight

    DeeVeeEight Well-Known Member

    If you are not saving the old part, try prying it open. It should be an easy fix if it has not turned solid.
     
  11. Daves72

    Daves72 I get jokes.

    That's a good idea. The non-metallic part looks like bakelite so I'll have to be careful not to crack it.

    I ordered a replacement relay on eBay last night. When I'll try to open the old one after it comes in. If nothing else, it will be neat to see how it's put together.

    That just reminded me that my thermo switch came in the other day.

    [​IMG]
     
  12. Daves72

    Daves72 I get jokes.

    Just a follow up, I got the Thermo switch and temp delay relay installed this evening and the blower is working properly now. When the engine is below 120F you get no low fan. Once it hits 120F, the Thermo switch opens which allows the temp delay relay to close and then the low blower comes on. I'm glad it's working and if anyone has a question please fire away.
     

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