DIY - How to get interior fan working again /w heater bypass tube
#46
Rennlist Member
Bump for a great thread! Installed the RS bypass and jumper and heating worked great this morning despite not having the blower at 40 degree morning here in Norcal.
#47
Hello,
I’ve done a major engine rebuild, which has the heater blower bypass. I’ve reviewed this thread (and others) and am trying to understand what the jumper does. I’ve tried the jumper with the fuse and without, no difference. With or without the jumper (and/or the fuse) my fan runs very fast on the blue dot and varying degrees of slow when not on the blue dot. If I press defrost, no change in fan spread, though I believe it’s supposed to go to maximum if you press this.
I did not have the car long enough to know how the system worked before I took it apart. Can someone provide some guidance to me on how the system originally operated?
Mine is 95 C2 Coupe, 3/94 build.
Thank-Brett
I’ve done a major engine rebuild, which has the heater blower bypass. I’ve reviewed this thread (and others) and am trying to understand what the jumper does. I’ve tried the jumper with the fuse and without, no difference. With or without the jumper (and/or the fuse) my fan runs very fast on the blue dot and varying degrees of slow when not on the blue dot. If I press defrost, no change in fan spread, though I believe it’s supposed to go to maximum if you press this.
I did not have the car long enough to know how the system worked before I took it apart. Can someone provide some guidance to me on how the system originally operated?
Mine is 95 C2 Coupe, 3/94 build.
Thank-Brett
Last edited by AV8TR; 04-26-2021 at 07:00 PM.
#48
Rennlist Member
The solenoid for the (rear) fresh air valve is energized when you put the transmission into reverse. With the front mixing chambers closed you can still get a little residual air coming through the recirculating flaps that are hidden below/behind the front seatbelt retractors (especially when they've torn slightly) depending on the air pressure in the cabin.
I don't think this functionality wasn't added until the end of ~MY95(?) (CCU version 12) along with the engine mounted fresh air flap. The 964 just sucks in exhaust fumes, just not even remotely as bad as a 964/993 cab with a cat bypass sitting in traffic...
I don't think this functionality wasn't added until the end of ~MY95(?) (CCU version 12) along with the engine mounted fresh air flap. The 964 just sucks in exhaust fumes, just not even remotely as bad as a 964/993 cab with a cat bypass sitting in traffic...
Last edited by c2_peter; 09-14-2022 at 03:22 PM.