BauerR

Hello again! Finally got my non-runner up and running only to discover a few other issues. Go figure, right? Haha

1) Anti-Lock light pops on about 100 or so feet after first moving. I'm thinking this might be a sensor issue at the wheel. If so, what's the easiest way to isolate the one in question? Remove each wheel and do it the hard way?

2) Climate control. Doesn't matter what setting i put it on, it always comes out the center. Even if i put it on the down setting it still blows out the center.
Thoughts on this?

SMTCapeCod

1) https://rennlist.com/how-tos/a/porsc...ight-on-376863 though that is pretty simplistic. CHeck for cleanliness of ABS magnets and tone ring on axle. Check wires for ABS sensor- pretty common that they get frayed and can either ground or be severed, especially around rear axles.

2) HVAC could be bad vacuum pods inside the dash, very common, 'comb actuator'. Also the contacts inside of the HVAC controller can get dirty, or the relay in the unit itself will fail.

Should be able to find ample posts on inspecting for faults between here and "Dwayne's Garage" 928 tech website.

BauerR

Welp, the Anti-Lock light went away after some driving. Wish they would all go away like that!

safulop

The 928 is an interesting car, she will often fix herself with regular use.

Shawn Stanford

Fro #2, check that all the colored vacuum lines behind the consold are connected to the R2-D2 looking thingy under the center vent.

Dave928S

Well worth carrying out PSD maintenance anyway, including fluid flush and cleaning of sensors, as they have often been neglected.

dr bob

'89 is of course the best model-year for the 928. Great driveline with no PSD, and no airbags.

Do check and clean the ABS sensors and the trigger rings at each wheel. Carefully inspect the wiring from sensor to chassis, including the barrel connectors hanging on the suspension. Those barrels have three holes in them with only two used -- one of the brake pad wear sensor and the other for the ABS wheel sensor. Clean the connections in the little barrels.

The symptoms you describe for the HVAC system are typical to having a failure in the vacuum part of the system. It defaults to center vent plus defrost vents. It also goes to full-hot, as the fail-safe position on the heater control valve is 'open'. Plenty of guidance on the diagnostic procedures atrting with the usual Tips Pages, and also look at the workshop manual for a great diagram that shows how all the pieces are connected, plus the "truth table" for control head positions vs vacuum. With no airbag, getting the new diaphragm for the center vent "comb flap" actuator is a LOT easier.

docmirror

I'm usually a 'diagnose' to failing unit and repair kind of guy, but with the HVAC system in these cars, it's one area where the whole thing needs to be rebuilt or replaced almost wholesale. The HVAC heads can be rebuilt back to like new, then replace all the vac lines, that rail of solenoids go bad, and the vac pots are high failure item as well. Same with the heater valve. I would just get a do-over and be done with it. Hopefully the AC pump is in good condition and you can at least retain that.

YMMV