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[Webby the Bear]

Hi guys,

I'm currently looking at electrics in cars at college. I've got to say I don't totally understand it but I have a basic concept that, with your help, I can put a guide together as to how to diagnose something electrical that goes wrong.

It just so happens that my car has an issue that cropped up this morning  that we can use to ''test the theory''.

But first we need to put the theory together.

SO

I gets in the car (the Ford  ) this morning and I pop it in reverse. When I do this the parking sensors should beep once (to tell me I've selected reverse) and then beep when I reverse near something. Simplez.

This morning however I put it in reverse and get a continuous beep.

So I'm thinking this is bad but also good as I really want to use the skills I'm learning in the real world. My guide is as follows. Please add stuff/tell me I'm wrong if you feel there's owt I've missed (but please, please, please remember it's me and put it in to baby language...literally!) 

1.) Simple things first. There are 4 sensors in the bumper. Makes sense to me to check for crap and debris on them.
2.) Next easiest thing... check the fuse and relays if this system has them. Obviously a visual is good but I believe the correct way is to check for continuity. Multimeter, touch the tabs, if it beeps the fuse is good.
3.) While we're there... check the socket that the relay/fuse go into. Again I think this is a continuity test but I could be wrong. Let me know if I am wrong.
4.) Getting tricky... get to the connection behind the bumper or in the boot. My understanding is that this will be the place the connection is grounded (or earthed  lol) so disconnect the connector, red lead in to each terminal, black lead to the chassis earth/ground and do a voltage test with the car on and gear stick in reverse (to check the voltage the system you're checking needs to obviously be on... if its not there'll be no voltage. simple but i was stupid enough to forget  )
5.) continuity test each sensor... if multimeter doesnt beep then the sensor(s) fubard and needs replacing.

Now please remember i'm only learning and trying to help myself and others by putting this together..... so if i get it wrong definitely tell me where i've gone wrong.... but nicely 

As for the circuit itself I havent yet looked at a wiring diagram and I don't know how the actual system works but this is just based on what i've seen so far of systems.

any input you have would be awesome.

cheers guys 

[doz]

Continues toan can be nothing more than a dirt on the senor. Always best to check the obvious before pulling the tools out

[Entwood]

All systems are different .. but IF it was an Omega .. there is a test connection with an object that looks like a fuse - actually a 300ohm resistor, that when removed puts the system into diagnostic mode, this will, by a series of beeps, tell you which sensor is faulty. There may be similar provision on yours.

You need to research the specs of the system you are dealing with

[Webby the Bear]

All systems are different .. but IF it was an Omega .. there is a test connection with an object that looks like a fuse - actually a 300ohm resistor, that when removed puts the system into diagnostic mode, this will, by a series of beeps, tell you which sensor is faulty. There may be similar provision on yours.

You need to research the specs of the system you are dealing with

I'm thinking wiring diagram, right? 

Whilst yes i agree thats what i need to do to solve this individual fault, would you say as a general checking procedure its right? 

[Entwood]

All systems are different .. but IF it was an Omega .. there is a test connection with an object that looks like a fuse - actually a 300ohm resistor, that when removed puts the system into diagnostic mode, this will, by a series of beeps, tell you which sensor is faulty. There may be similar provision on yours.

You need to research the specs of the system you are dealing with

I'm thinking wiring diagram, right? 

Whilst yes i agree thats what i need to do to solve this individual fault, would you say as a general checking procedure its right? 

IMHO No ... you need to research the system properly, manufacturers notes / TIS / handbooks etc etc .. a wiring diagram will NEVER give you diagnostic information.

eg .. the wiring diagram for the omega shows the test 300ohm fuse. Does it tell you the audible codes and what they mean ?? Nope .. it doesn't actually tell you what it does .. its just a 300 ohm resistor to the wiring diagram.

[STMO123]

Here's my list:

1.  Take it to someone who knows how to fix it.

2. Pay them.

[Webby the Bear]

Here's my list:

1.  Take it to someone who knows how to fix it.

2. Pay them.

Thanks for the useful input STE-HOMO 

Entwood... thanks for the comments.

The reason I said about the wiring diagram was to locate the various wires that you may need to test. Having thought about it I suppose if the general logic is to first off test the part that's faulty then it makes sense to go straight to that and likie you say the bulletins would help...

e.g. a google search suggests people think its one particular sensor. so find the connection. probe and test it. that will show the condemned sensor.

Having said that wouldn't a wiring diagram be good to suss out which colour wire goes to which sensor (assuming you could get the diagram in the first place...it isn't in the Haynes).

 

[henryd]

Here's my list:

1.  Take it to someone who knows how to fix it.

2. Pay them.

Thanks for the useful input STE-HOMO 

Entwood... thanks for the comments.

The reason I said about the wiring diagram was to locate the various wires that you may need to test. Having thought about it I suppose if the general logic is to first off test the part that's faulty then it makes sense to go straight to that and likie you say the bulletins would help...

e.g. a google search suggests people think its one particular sensor. so find the connection. probe and test it. that will show the condemned sensor.

Having said that wouldn't a wiring diagram be good to suss out which colour wire goes to which sensor (assuming you could get the diagram in the first place...it isn't in the Haynes).

 

Are the sensors standard or aftermarket

[bigbadee]

Quietly Confident
Elite 3.2 V6 (LPG)










Re: Electrical Diagnostics

« Reply #2 on: Today at 14:07:23 »

Quote


more infor please how do i read the bleeps just about to look at a new mig and the parking sensors dont seem to work thanks--------------------------------------------------------------------------------

All systems are different .. but IF it was an Omega .. there is a test connection with an object that looks like a fuse - actually a 300ohm resistor, that when removed puts the system into diagnostic mode, this will, by a series of beeps, tell you which sensor is faulty. There may be similar provision on yours.

You need to research the specs of the system you are dealing with

[Webby the Bear]

Here's my list:

1.  Take it to someone who knows how to fix it.

2. Pay them.

Thanks for the useful input STE-HOMO 

Entwood... thanks for the comments.

The reason I said about the wiring diagram was to locate the various wires that you may need to test. Having thought about it I suppose if the general logic is to first off test the part that's faulty then it makes sense to go straight to that and likie you say the bulletins would help...

e.g. a google search suggests people think its one particular sensor. so find the connection. probe and test it. that will show the condemned sensor.

Having said that wouldn't a wiring diagram be good to suss out which colour wire goes to which sensor (assuming you could get the diagram in the first place...it isn't in the Haynes).

 

Are the sensors standard or aftermarket

they are standard mate 

[Entwood]

Quietly Confident
Elite 3.2 V6 (LPG)










Re: Electrical Diagnostics

« Reply #2 on: Today at 14:07:23 »

Quote


more infor please how do i read the bleeps just about to look at a new mig and the parking sensors dont seem to work thanks--------------------------------------------------------------------------------

All systems are different .. but IF it was an Omega .. there is a test connection with an object that looks like a fuse - actually a 300ohm resistor, that when removed puts the system into diagnostic mode, this will, by a series of beeps, tell you which sensor is faulty. There may be similar provision on yours.

You need to research the specs of the system you are dealing with

Have a good read here .. all explained .. you may have to go back into the thread a tad to find the description of where the test socket is 

http://oldsite.omegaowners.com/forum/YaBB.pl?num=1279621948/30#30

[martin42]

err its a ford fusion,best to read the manual webby,and see whats going on 1st

[Webby the Bear]

err its a ford fusion,best to read the manual webby,and see whats going on 1st

thanks mate. as said this wasn't really a way of fixing this... just wanted to really discuss electrical diagnosis procedure as a generic thing 

[symes]

If you read OP's thread -IN Morning_____--There was probably ice on sensors=leave it alone it will be fine

[martin42]

i dont get ice on my car lol