89 190 2.6 Hvac problems, & Tach Inop???
02-15-2006, 08:50 PM
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99 323i, 01 330i, 89 190E 2.6
89 190 2.6 Hvac problems, & Tach Inop???
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Yes, I'm the annoying new kid on the board who knows nothing about MBZ, but want to learn!
I just bought a 1989 190e 2.6 VIN#WDBDA29D9KF621994. This is my first MBZ, so I'm basically clueless...
I love the car, but I have found that my climate control system is basically just there for looks 
First, Air will blow out dash vents ONLY - (Not defroster vents, but "face vents"?)Update: Air flows mainly from dash vents but a slight amount of air is coming out of the defroster vent at all times.
I drove 260 miles to buy the car... When I headed home in it, the outside temp was around 80 degrees. The temperature soon fell below 40 degrees and I found that the heat doesn't work at all in the car! With the dial set to full heat and in any mode, there is no heat coming from any vent anywhere. The heater core cooling hoses ARE connected... So where do I start looking? I did a bit of searching and my head is spinning from all sorts of vacuum diagrams, wiring etc... It's not fun driving in 35 degree weather with no heat and dash vents that will not close... (broken) And yes, the coolant is up to temp and never drops below 80.
Second...
My Oil pressure gauge is erratic (i'm assuming the pressure sensor is faulty... other ideas?)
My tachometer doesn't move at all. I have checked all fuses and they are fine...
Along with these two cluster issues, I have no outside temp display... It's just blank...
Again, this is my first MBZ and I don't even know where to start looking.
All help is appreciated!
-Doug
Yes, I'm the annoying new kid on the board who knows nothing about MBZ, but want to learn!
I just bought a 1989 190e 2.6 VIN#WDBDA29D9KF621994. This is my first MBZ, so I'm basically clueless...
I love the car, but I have found that my climate control system is basically just there for looks First, Air will blow out dash vents ONLY - (Not defroster vents, but "face vents"?)Update: Air flows mainly from dash vents but a slight amount of air is coming out of the defroster vent at all times.
I drove 260 miles to buy the car... When I headed home in it, the outside temp was around 80 degrees. The temperature soon fell below 40 degrees and I found that the heat doesn't work at all in the car! With the dial set to full heat and in any mode, there is no heat coming from any vent anywhere. The heater core cooling hoses ARE connected... So where do I start looking? I did a bit of searching and my head is spinning from all sorts of vacuum diagrams, wiring etc... It's not fun driving in 35 degree weather with no heat and dash vents that will not close... (broken) And yes, the coolant is up to temp and never drops below 80.
Second...
My Oil pressure gauge is erratic (i'm assuming the pressure sensor is faulty... other ideas?)
My tachometer doesn't move at all. I have checked all fuses and they are fine...
Along with these two cluster issues, I have no outside temp display... It's just blank...
Again, this is my first MBZ and I don't even know where to start looking.
All help is appreciated!
-Doug
02-16-2006, 09:45 AM
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2003 C230K Sport Coupe, 1986 190E 2.3
First HVAC is vacuum controlled. Check all Vacuum rubber connectors under the hood as well as leading into the car. Sounds to me you have a serious vacuum problem or bad HVAC unit. Strange since the HVAC unit defaults to full heat when no vacuum is present and out the dash vents. You could have a faulty Aux Water pump or Heat Valve as well. The Heat valve defaults also to open so you should have full heat. But the Aux Pump when not working will not pump hot coolant into the heater core so that will give you limited luke warm heat. Check for vacuum leaks first, then put your hand on the Aux Pump when idling and heat set to full defrost and see if you can feel it working, it is located below the Coolant Tank mounted to the frame rail.
Also verify that the heater core is connected and that the last owner did not bypass it due to a leak.
As for the Tach and bouncy Oil Pressure gauge. Well it could be a bad or lose ground behind the cluster. Or just a bad tach and bad sensor for the Oil Pressure. That one is a little more tricky since it could be many things. First verify all fuses are actually good. Those old fuses are junk in these cars. The factory ones we aluminum and the contact points in the fuse box are copper if I recall correctly. Making the matting surface between two dissimaliar metals which corrodes quicker and can lead to premature fuse failure. One of the first things I did with my W201 was replace all fuses.....
Also check out 190revolution.net's forums. They are W201 only forum..... A great resource for DIY'ers!
Also verify that the heater core is connected and that the last owner did not bypass it due to a leak.
As for the Tach and bouncy Oil Pressure gauge. Well it could be a bad or lose ground behind the cluster. Or just a bad tach and bad sensor for the Oil Pressure. That one is a little more tricky since it could be many things. First verify all fuses are actually good. Those old fuses are junk in these cars. The factory ones we aluminum and the contact points in the fuse box are copper if I recall correctly. Making the matting surface between two dissimaliar metals which corrodes quicker and can lead to premature fuse failure. One of the first things I did with my W201 was replace all fuses.....
Also check out 190revolution.net's forums. They are W201 only forum..... A great resource for DIY'ers!
02-16-2006, 03:32 PM
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the face vents are for fresh air only... close those vents!
the oil guage? is it irratic at cruisning speeds or between idle and higer rpm's? Should read like .3 bar at idle, and 3 full bar at anything about 3,000 rpm...
as for the rest of the HVAC issues... same issues here...
the oil guage? is it irratic at cruisning speeds or between idle and higer rpm's? Should read like .3 bar at idle, and 3 full bar at anything about 3,000 rpm...
as for the rest of the HVAC issues... same issues here...
02-17-2006, 01:19 AM
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99 323i, 01 330i, 89 190E 2.6
I know the vents are for non heated fresh air, but they won't close... They are broken! 
I did a little more digging under the hood (and in the daylight!)
and found that the P.O. Put a valve on the heater core inlet hose.
I opened this valve and hot air blows from the defroster and side vents now!
Atleast I have some heat!
The tach is completely dead, but all other gauges work...
The oil pressure gauge will literally go crazy and read 0 when on the freeway or .7 with the car off, but usually stays at full 3.0 when the engine is running. So now I'm thinking bad ground for the pressure sensor, but still don't know about the tachometer since it never even tries to work...
Along with the cluster problems, I also have a bulb out and the odometer quit about 2 months ago... (documented...)
So how do I get the instrument cluster out?
TIA-
Doug
I did a little more digging under the hood (and in the daylight!)
and found that the P.O. Put a valve on the heater core inlet hose.
I opened this valve and hot air blows from the defroster and side vents now!
Atleast I have some heat!The tach is completely dead, but all other gauges work...
The oil pressure gauge will literally go crazy and read 0 when on the freeway or .7 with the car off, but usually stays at full 3.0 when the engine is running. So now I'm thinking bad ground for the pressure sensor, but still don't know about the tachometer since it never even tries to work...
Along with the cluster problems, I also have a bulb out and the odometer quit about 2 months ago... (documented...)
So how do I get the instrument cluster out?
TIA-
Doug
02-22-2006, 02:34 PM
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The instrument cluster is actually quite easy, i've pulled mine off (to replace the speedo when the odometer quit)...
Reach behind the cluster, AND PUSH.... really really hard, and OUT IT COMES... Its just held in with pressure... to put it back in just push it in firmly and it goes back perfectly.
Obviously you will have tor remove the speedo cable and wireing harness, but that only takes a few seconds.
Should be able to buy a new intrument cluster on ebay for CHEAP. I bougt a new speedo for about 25 dollars. Milage was obviously different, but on a 15+ year old car, i dont think it matters anymore.
Reach behind the cluster, AND PUSH.... really really hard, and OUT IT COMES... Its just held in with pressure... to put it back in just push it in firmly and it goes back perfectly.
Obviously you will have tor remove the speedo cable and wireing harness, but that only takes a few seconds.
Should be able to buy a new intrument cluster on ebay for CHEAP. I bougt a new speedo for about 25 dollars. Milage was obviously different, but on a 15+ year old car, i dont think it matters anymore.
