'89 240 brake light + relay help needed

Hey Folks,

I have an '89 240DL, the brake lights are all out. Bulb failure light
comes on when brake pedal is presses. I've scoured google groups but
still have some questions.

Fuse # 7 is good
fuse port carries current
brake light switch has continuity
switch wires get current as needed

From what I've read I know that I need to check the relay, #54, etc.
and check the light sockets themselves. But I have some prodedural
questions.

1. How exactly do you get that damn cap/plug off of the relay?? It has
a lever type thing in the center of the wires, but no amount of
pulling, prying, etc. will loosen it. Do I need to pry it off with a
screwdriver?

2. To check the relay poles, will a standard light-up circuit tester
pen do the trick? (not if the cap is off, I know) Do I need to use a
multi tester? How does one test the ports on the relay?

3. Would someone please be so kind as to breakdown the process of
testing the taillight/brakelight sockets for current, etc.? Where
exactly are you supposed to probe on the light assembly?

I'm pretty new to using the multitester and circuit tester so any
guidance advice is appreciated.

Thanks, and this is one hell of a research archive.

Chris

 

umm...anyone...help? Please?

 

The lever type thing is to latch the relay to the wire harness. You
need to pop the cap off where the red of the case and black of the base
intersect.

However, first check if the relay is OK by using a jumper wire (eg clip
lead) joining the terminals marked 54 and 54L on the car harness. (You
have to read the numbers on the relay and transpose them back to the
harness.) Press the brake pedal down, if the left brake light goes on,
then you have a bad relay. If not, then you have another problem.

 

Thanks for the info Mike.