Heater Relay Location?
 

1988 911 Targa Turbo Slope (Option 505)

Does anyone know where the relay for the footwell heater blowers are located? If so...what would the part number be and where is it located? I have been troubleshooting the heater system and the Porsche factory schematics show a relay for these bad boys to be in the engine compartment. This does not jive with the part numbers on the relays in the rear when doing parts lookups with Porsche parts department and PET. The fresh air motor was bad and I have replaced. Middle console switch working and baffles operating. Dash sensor seem to be operating. All fuses fine. Footwell blower motors good. Relay is the next target on radar screen. Any help appreciated.

The relay is in the back on the driver's side of the engine compartment behind a plastic cover with one or two other relays and three fuses.

and the part number is not 911 618 153 00?

Do you have a picture? There are four relays behind the cover. The one nearest the front of the car is the rear window heater relay(As best I can decifer from the manuals and the cover). Next to it is the delay ignition cutoff relay (Know this to be true). Next to that one is a black round relay. I do not know what it controls. Next to that is a tall yellow relay that I no idea what it controls. Also of interest is that there is a relay socket mounted vertically that is empty near the ignition control unit. I have no information as to what that is either. What is scarey is that the Porche factory manual schematics show the position that the delay ignition cutoff is in to be the "blower relay".

Yep, that's weird, in my car the second relay is for the blowers (all three). My car only has two relays. There is normally an empty socket for a round style relay around there someplace. I'm guessing that since your car is a turbo slant nose that things must be different. Hopefully someone with a turbo, at least, will chime in. What are the part numbers of the non-round relays?

Steve, or whomever-does anyone know whether this is a multiple coil relay within one case? My footwell blowers work in position 2 regularly, but in positions 1 and 3 intermittently (although it seems if you get it to start in position 3, it doesn't shut itself unintentionally). Given the erratic nature of this, and that the floorboard connector is good, I suspect that I have a funky relay, but at 178.00 non-returnable, I'd like to understand it before I plunge.

It wouldn't be a big deal, but the difference between pos 2 & 3 is huge, in terms of heat when your sitting.

Steve,
The relays in question part numbers are as follows:
911.615.118.01 - Yellow - Square relay
911.615.109.01 - Black - Round Relay

Thanks

The engine compartment controller is the one in the engine compartment. The footwell blower relay should be in the front trunk.

Which relay are you suggesting in the front?