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My AC works great and my heat, but the power to the CCU cuts out, and none of the controls work, NO power what so ever except for the back lights on the face, NO AC, NO Heat, NO fan, then a few minutes later everything works great, ??
The CCU needs three powers: K2 - #30, K35 - #15, K29 - X.
The X power (accessory) comes thru a connector behind the glove box.
Thank you for that info, But I have know idea what K2-#30, K35-#15, K29-X means or where they're located, Please inform me on this, and how to get to the connections. I'm new to the 964 chassis and its electrical system. I look forward to learning
I also forgot to mention that when the CCU power goes down so does the power to my oil cooler fan and air conditioning fan... bad ground ? do they share so sort of wiring and where would i find it ?
The CCU connectors are probably OK. They are difficult to extract, and I do not expect them to have fallen out.
The fuse holders in the 964 are sometimes loose, causing intermittent connection. The main power to the CCU is coming from Fuse 1. This is also feeding the front blowers, and is often damaged due to the high current, especially due to failing blower motor bearings.
The CCU have several power supplies and fuses, these can be tested with a voltmeter on the CCU harness connectors. I would recommend to try to wiggle the fuses too.
Pin K1, GND
Pin K2, Terminal 30, permanent +12V, Fuse 1
Pin G35, Terminal 15, switched +12V, Fuse 17
Pin G29, Terminal X, switched +12V, Fuse 28
Pin G17, Terminal 58d instrument lights, Fuse 36
Can some tell me more about the ground and where to find it ? and how I can check it,
Oil Cooler Temperature Sensor – 22.6 to 3.8 KOhms – G12 gn/bkExcessive oil temperatures read at the oil cooler will also cause the CCU to disengage the compressor to reduce load on the engine. Test resistance from G12 to G18 as above, looking for faulty readings like an open circuit.
Sensor Ground – G18br/bl to ground
All sensors get ground from G18. Verify that G18 has a strong connection to ground. A bad ground on G18 can cause a host of problems.
The CCU connectors are probably OK. They are difficult to extract, and I do not expect them to have fallen out.
The fuse holders in the 964 are sometimes loose, causing intermittent connection. The main power to the CCU is coming from Fuse 1. This is also feeding the front blowers, and is often damaged due to the high current, especially due to failing blower motor bearings.
The CCU have several power supplies and fuses, these can be tested with a voltmeter on the CCU harness connectors. I would recommend to try to wiggle the fuses too.
Pin K1, GND
Pin K2, Terminal 30, permanent +12V, Fuse 1
Pin G35, Terminal 15, switched +12V, Fuse 17
Pin G29, Terminal X, switched +12V, Fuse 28
Pin G17, Terminal 58d instrument lights, Fuse 36
Cheers,
Tore
Pin K1, GND
please tell me more about this one, and where can iI find it ?
Sorry for any confusion, this is a pin designation on the CCU harness, not a fuse.
I would start checking the fuses, then go on with checking the power supplies on the CCU.
Here's a pic of the CCU harness connectors:
Cheers,
Tore
While I agree with Tore, the connectors don't tend to come loose from the CCU, BUT the wires themselves can pull free from the back of the connectors. I recently experienced this in fact after I removed and reinstalled my CCU. I think it was the #1 wire that came out, no doubt from my man handling the harness and connectors trying to remove them from the back of the CCU.
My first plan of attack my intermediate working CCU,
1 check all the fuses 1, 17, 28 and 36. 2 lift the fuse box and check for any lose wires, 3 clean the the connection from the ground strap to the chassis, 4 clean the ground connections to the chassis behind the fuel gauge, 5 check for a strong ground on pin K 1. 6 check for continuity. between pin K 1 and G18 on the CCU, 7 check for 12V on pins K2, G17, G29, G35,
I don't plan on checking the oil cooler sensor or the evaporator sensor or the AC FAN sensor because they all work when I have power to the CCU, which is 75% of the time. because of that I'm assuming it's not my relays. I also jumped the the relays and the fans on the AC and Oil cooler come on only when there is power to the CCU, but when there is no power to the CCU jumping does no good.
If I don't have a strong ground, I'm thinking of running a wire from the battery to the chassis ground connection behind the fuel gauge, I'm assuming that the CCU harness gets it's ground from there, If any one has experienced this before, please chime in
At a glance the pins on the harness look fine as does the wiring, Let the fun begin
Did all that last night, I had good ground, So far the power has not cut, I drove a bunch last night and today its 88 deg and 50% humidity, its blowing cold... 36 deg at the vent, I think thats good. and all the fans are working in and out side of the car,
06-12-2017, 11:02 AM
NO Power to the CCU, sometimes ... please help
