86 560SEL fuel pump relay going bad??

[rsmartin]

this morning my car wouldn't start. turned key, all the idiot lights on, car turned over but wouldn't start. turned off, turned key on again, noticed i didn't hear the fuel pumps run when i turned the key as they always buzz for a second when i first turn the key on.

so i turn to my trusty MB CD and look up fuel electrics. check all fuses, none blown. so pull all three relays that are between the firewall and the engine wall (whatever that's called). gave them a shake and a few taps and put them back in again.

turned key on and still not fuel pump sound. turned key on again, and this time hear the usual buzz. turn key to start and motor fires right up

so now i'm wondering... which of the two black relays is the fuel pump relay. the one closest to the center of the car? or the second closest to the center?

AND.. is this thing going to fail while i'm driving. Friday, as i was driving out of my drive way, the car shut off twice. it started right back up each time, but shut off twice in a row like that. it's never done that before.

[mak]

Yes from the symptoms, most likely its the fuel pump Relay failing at the solder joints . To be on the safe side it is best to replace the fuel and over voltage relays. both are liable to become non functional at this stage due to ageing.

They can be repaired by re-soldering the solder joints ,as i did a few years back,still operational.
mak

[rsmartin]

any directions on the resoldering? do you have to crack open the case somehow?

[mak]

the pin base has the indented area ,simply pry till you can pull the top case off the pin base.
the circuit board is delicate and requires a deft hand to re-solder the joints which look in a faded condition with a hairline crack.
mak

[rsmartin]

thanks, maybe i can do it

just finished soldering new dash light bulbs onto the circuit board of the climate control module on my wife's 2001 Chrysler Town & Country van. the dealer said this was a non-servicable part and wanted me to part with upwards of $500 for a new module. guess it was servicable afterall!! lights up like a Christmas tree again.

at least Mercedes makes it a little easier with replaceble bulbs, at least on my 126 body cars they do.

[rsmartin]

took the FPR apart. looked very closely at the board and noticed that the largest solder point in the middle of the board that appears to be a significant point of the relay coil to the board appeared to have a crack or something looked a little weak about it. touched it up with the soldering iron and added just a tiny drop of new solder just for kicks and giggles.

put the FPR relay back and car started right up!! yeah.. we'll see how long it lasts. probably gonna be hard to get my wife to drive it though. once a car shows signs of cutting out without warning, she's pretty much done with it!!

also in searching about this problem, the issue of the overload protection relay came up. is that something that would cause my ABS light to turn on?

generally on the first time using the brakes coming to a very slow stop, like at the end of the driveway, the brake pedal feels like it's doing the ABS thing (kinda vibrates), and then soon after the ABS light comes on.. are the two connected?