 Auxiliary Heater Fan Works, but not by the floor lever? |
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| dgraves |
  Mar 18 2019, 03:20 PM
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#1
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1974 914 2.0  Group: Members Posts: 180 Joined: 6-June 16 From: Montana Member No.: 20,076 Region Association: Rocky Mountains  |
The heater in my engine compartment does in fact work when I hook up directly to the battery. Unfortunately it does not work when I pull the red lever on the floor in my cab. How can I check if I have a correct circuit?
Thanks in advance. |
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| BeatNavy |
Mar 18 2019, 03:26 PM
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#2
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region 
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Most likely the ground connection at the lever became disconnected. If you unbolt that lever and gently start to pull it out of the tunnel you should see a little tab with a green wire connected to it. On my '72 the wire was disconnected and hiding in the tunnel. I had to fish it out of the tunnel with a dental pick and reconnect it to the lever. It grounds that circuit when the lever is fully lifted.
Check that first. If that's connected and grounding properly when the handle is lifted, then you have to look to issues with the relays/relay board. |
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| dr914@autoatlanta.com |
Mar 18 2019, 04:07 PM
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#3
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914 Guru Group: Members Posts: 7,816 Joined: 3-January 07 From: atlanta georgia Member No.: 7,418 Region Association: None |
I agree, either the lever is not grounding, the relay is bad or the rear fuse on the relay board is bad or not making connection
QUOTE(BeatNavy @ Mar 18 2019, 02:26 PM)  Most likely the ground connection at the lever became disconnected. If you unbolt that lever and gently start to pull it out of the tunnel you should see a little tab with a green wire connected to it. On my '72 the wire was disconnected and hiding in the tunnel. I had to fish it out of the tunnel with a dental pick and reconnect it to the lever. It grounds that circuit when the lever is fully lifted. Check that first. If that's connected and grounding properly when the handle is lifted, then you have to look to issues with the relays/relay board. |
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| 914_teener |
Mar 18 2019, 06:13 PM
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#4
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914 Guru Group: Members Posts: 5,194 Joined: 31-August 08 From: So. Cal Member No.: 9,489 Region Association: Southern California |
This circuit works as a switched ground. The lever grounds the circuit. MAKE SURE that all the connection and contacts are clean.
The trace wire runs through the tunnel and then into the pin harness at the regulater plate. You can uplug the pin harness and then check for continuty with a DVM. If that rings out you then need to check to check the trace on the regulater plate. More than likely the connections are dirty. Check those first. |
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| 914_teener |
Mar 18 2019, 06:26 PM
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#5
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914 Guru Group: Members Posts: 5,194 Joined: 31-August 08 From: So. Cal Member No.: 9,489 Region Association: Southern California |
QUOTE(dr914@autoatlanta.com @ Mar 18 2019, 03:07 PM) I agree, either the lever is not grounding, the relay is bad or the rear fuse on the relay board is bad or not making connection QUOTE(BeatNavy @ Mar 18 2019, 02:26 PM) Most likely the ground connection at the lever became disconnected. If you unbolt that lever and gently start to pull it out of the tunnel you should see a little tab with a green wire connected to it. On my '72 the wire was disconnected and hiding in the tunnel. I had to fish it out of the tunnel with a dental pick and reconnect it to the lever. It grounds that circuit when the lever is fully lifted. Check that first. If that's connected and grounding properly when the handle is lifted, then you have to look to issues with the relays/relay board. What George said. |
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| dgraves |
Mar 18 2019, 07:50 PM
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#6
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1974 914 2.0 Group: Members Posts: 180 Joined: 6-June 16 From: Montana Member No.: 20,076 Region Association: Rocky Mountains |
QUOTE(BeatNavy @ Mar 18 2019, 03:26 PM) Most likely the ground connection at the lever became disconnected. If you unbolt that lever and gently start to pull it out of the tunnel you should see a little tab with a green wire connected to it. On my '72 the wire was disconnected and hiding in the tunnel. I had to fish it out of the tunnel with a dental pick and reconnect it to the lever. It grounds that circuit when the lever is fully lifted. Check that first. If that's connected and grounding properly when the handle is lifted, then you have to look to issues with the relays/relay board. Green wire is connected. The lever all looks pretty clean. No corrosion. I'm assuming the green wire is the power? Is this true? On my '74 2.0, is the relay board in the engine compartment behind the driver's seat? Is there more than one relay in there? Thanks to all. |
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| SirAndy |
Mar 18 2019, 08:02 PM
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#7
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Resident German Group: Admin Posts: 41,606 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
QUOTE(dgraves @ Mar 18 2019, 06:50 PM) I'm assuming the green wire is the power? Is this true? Technically, sort of, no ... As already mentioned above, it is switched ground, which is very common for European cars of that area and used extensively in the 914. Meaning, the power goes to the blower motor from the relay board in the back, the green wire is the blower motor *ground* which is closed to complete the circuit when you pull up the lever. (IMG:style_emoticons/default/shades.gif) |
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