1989 300 SE A/C want work
 

The compressor will not come on.The fan is working.
The plug going to the compressor has no power.I have checked all the fuses in the box and they are all good.Is there a fuse between the fuse box and the air compressor.
Thank You
Larry

there's a little oblong black plastic box on the drivers side near the fender well... probably 3 inches long... inside there is a strip fuse... often the problem.

I tend to keep one on the shelf as a backup... haven't had to use it yet.

:) Can you get me a little closer to it.Is it close to the fuse box,Is if on the wheel well?
Thank You
Larry

Pop your hood.

Look in the vicinity of the brake master cyl. reservoir. Just in front of it maybe 9-12 in.(I'm guessing) there's a wall that curves in this general area. Not too far in front of it is the fuse holder mentioned above. You open it up and there will be a metal strip inside.

I found it and it :( was ok can you think of anything else.
Thank You
Larry

"ok" can be deceiving...

I would get one from the dealer and installl it and see if there is still a problem

two bucks

problem is with ac relay
 

Replace kilma AC relay or remove from housing and resolder connections.





Anthony

The bar fuse is for the blower motor anyway.

Have you put gauges on the system yet? When it is low on refrigerant the low pressure switch inhibits the clutch circuit to protect the compressor.

The first step in troubleshooting the refrigeration portion of the a/c system is to get pressure and temperature readings.

Good luck,

How to check compressor clutch. Automatic AC
 

To check the compressor clutch operation.

First check low pressure switch. The one without wires coming out of the switch, just 2 spade connectors. If you have 12Vdc on one leg and not the other you may have a bad switch or most likely low freon. Jump the 2 connectors together and see if the compressor comes on if it does then check freon pressure. If low, charge and check for leaks, if not low then replace switch and recharge system.

Next step if all is ok above;

1. Speed sensor on back of compressor. Should read 0.3v AC with DVM. Can read a little lower such as 0.28Vac and be OK dependant on meter used.

To test; remove AC relay and jumper pins 87 and 15. This will turn on the compressor and keep it on. ( pin 15 )is 12Vdc when ignition is on. Pin 87 goes to compressor.

2. If your car is running correctly and I hope it is Check between TD and 87Z this is the Engine speed signal going to the AC relay. Should read 6Vdc - 8Vdc and will increase when the RPM increases. This is a square wave signal if looked at with a scope.

3. Temperature sensor input this is only a factor if you are using autoAC. Always test AC with max blower and AC dial set to min.

4. Bad connections to the items above. I would suspect the AC relay. Remove the cover and check for bad solder connections. Or replace relay.


Good luck.
Anthony Bridges

AC want work
 

I bought this compressor used because I thought the other on was bad. We charged the system but the compressor would not work. There is no power on the plug that plugs in the compressor. I will check the ac relay tomorrow and get back to you
Thank You For all the help
Larry

1989 300se
 

Can you tell me witch relay is the ac there nothing on the fuse cover about the relays.The cover for the relays is missing.
Thank You
Larry

Relay location
 

The relay module you are looking for is a littler bigger than a pack of cigaretts. It is located behind the battery, behind a plastic cover and should have a number like 0025451305 KILMA or 3701130 KAE. There will be 2 relays that look alike but with different numbers. The other relay will be your fuel pump relay. If you look at the bottom of the relay, where the pins are you should see lables by each pin. That was what I was refering to.


Good luck

Anthony Bridges

1989 300 Se
 

There are 6 relays and they all look the same I can't tell witch one is the ac they are not named.
Thank You
Larry

What car are you looking at?
 

Are we talking about an 89 300CE W124 ? If so then

Originally Posted by cnctony
The relay module you are looking for is a littler bigger than a pack of cigaretts. It is located behind the battery, behind a plastic cover, There are only 2 relays there not 6. The 6 metal can relays 1" x 1" are behind the fuse box on the drivers side. Look on other side of car. Did you see the picture in the previous post? That is what you are looking for. It does have a part # on it.

It may be hard to see unless you REMOVE THE BLACK PLASTIC COVER behind the battery.

Here is a list of Cars that this relay fits, and a cross reference list of other popular AC relays that can be used.

Mercedes 190E 201/103 2.6 Ltr. 87-89
Mercedes 260E 124/103 2.6 Ltr. 87-89
Mercedes 300CE 124/103 3.0 Ltr. 88-89
Mercedes 300E 124/103 3.0 Ltr. 86-92
Mercedes 300SEL 126/103 3.0 Ltr. 88-91
Mercedes 300TE 124/103 3.0 Ltr. 88-93

FOOTNOTE:
POPULAR EQUIVALENT CROSS REFERENCES:
3701130
MB005837
R114012156
R114070276