Hopefully this SDL cluster is still in this car, if so I'll snatch it up and go from there. Probably shelf my current like new one until I want to spend $250 to fix it properly.

Also picking up a 2.47:1 LSD for the 420 and the KE for it too.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Jumping at the Klima for pins 7 and 10 worked, compressor came on for a while and stayed on. Bad PBU or Pressure switch?

Batt light came on too, almost like the alt isn't charging enough. Just what I wanted. I'll pull the reg in a bit and see what the deal is on that.

Also, temp came up to 100°C rather quick... aux fan was on and pushing. I have flushed the rad/system well, Xerex coolant, new clutch too.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Jumping 7 and 10 means the PBU is good since the PBU sends a signal through pin 10.

What I think is that the Klima is bad or one of the compressor interrupts is in effect. Again, no engine rpm, no compressor rpm, inadequate system pressure (I think, I don't remember if the pressure switch is upstream or downstream of the Klima). Could also be a bad Klima or wrong Klima. Gassers have a different engine rpm input to the Klima.

Sixto

Klima is new.

I also bypassed the pressure switch on the dryer. Would I have to evac the system to install a new one? Any ohm readings I can do to it to verify?

RPM sensor on the comp could be bad?

What do you think about getting hot so quickly?

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Somthing is amiss here.

7 is the line to the clutch.

10 is the line through the low pressure switch to the CCU. This is an open line unless the CCU calls for the compressor to start and then the line goes to ground. The low pressure switch is in series on this line and needs to close to allow the ground signal to reach the Klima.

It does not appear possible to engage the clutch by jumping sockets 7 and 10. If you want to engage the clutch, jump sockets 7 and 5. 5 provides battery voltage to the Klima.

That's Texas for you

I looked through my old posts. The PBU sends a ground signal to the Klima to engage the compressor. The Klima in turn sends a +12V signal to the compressor.

The PBU signal (Klima pin 10) goes through the pressure switch so you can test if that switch is good by checking for a PBU signal with the switch connected vs disconnected.

I posted earlier how to check for engine (Klima pin 2) and compressor (Klima pin 9 and 11) rpm using AC voltage mode.

There's also the 115*C switch (Klima pin 12) by the upper radiator hose fitting and the full throttle microswitch (Klima pin 6) along the throttle linkage that influence the Klima.

It's not nearly Texas hot where I am and as soon as my Klima acted up I dumped it for an ice cube relay. You learn to drive an SDL with one eye on the temp gauge so it's unlikely you wouldn't turn off the AC if temps got to 115*C.

I don't know about getting to 100*C quickly. Clutch fan? When that happened to my SDL is was the -14- head saying goodbye but all the classic symptoms were there as well.

Sixto

That's right. When the PBU isn't sending a signal to the compressor the pin probably sits at some high value. So PBU is back on the suspect list.

Sixto

I can pull the PBU from the 420, it was reman in ~2001 or so. Then go from there.

I know the fan switch on the block needs to be replaced.

Any ideas on the batt light coming on?

I do not mind shelling out for parts, provided that is the problem. So should I go with a new PBU?

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Run the engine and put the CCU in the cooling mode.

Check for ground on socket #10 of the Klima. If you get the ground then the CCU is not the problem. If you don't get the ground, jump the low pressure switch and see if you get the ground. If not, then the CCU is the culprit.

How do I check for ground there at No 10?

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Continuity to a good known ground......

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Continuity.

One lead to the negative post on the battery. One lead to the socket.

Either you have it........or you don't.

I'll reread this tomorrow, I've had one toomany beers this evening.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

i just got my 300SDL 2 weeks ago. the A/C worked when i got it, but now it doesn't seem to stay running when it's really hot. if i disconnect the #5 fuse, and reconnect, it will come back on...sometimes for 2 minutes, sometimes for longer. the turbo is also bad (bushings bad, dumping oil into the intake), so i'll be fixing this first

Resoldering my CCU now. Will report back...

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]