A question on starter relays

1989 Jeep Cherokee Laredo L6 4.0 5sp

Has been running top notch for quite some time now, in fact was o ut and about running Christmas errands yesterday with no indication of abnormality.

Decided to go get a pizza for supper, jumped in and while driving all electrical flashed off, lights running stereo all if it. It was no more than 1/3 of a second of "off"
A mile or so later it happened again 1/3 of a second and all back to normal.

Out of truck, get pie, in to truck and NOTHING.
No click on ignition, no lights, no starter - nothing. Like no batter was persent under hood.

I know battery is good (less than a year old) but wiring is probably original. just before I call wife to make the rescue I grab the POS battery wife and give it a good shake - more out of frustration than anything else.

I hear three clicks. Click (Like a relay closing) Click (Like relay contacts opening up) CLICK like positive closure of a relay.

Looking at the wiring diagrams today it looks like the only real MASTER throughput of power is the Starter relay which most all vehicle power passes through before going from battery out in to vehicle.

Am I missing anything in my observation of power distribution and could my starter relay be the issue?
- AND -
Looking online I see prices from $19.99 to $64.99 Autozone, Schucks (Checker O'Riley) NAPA
Is there any actual difference in quality - is it a get what you pay for part?
My selection manufacturers are BWD Automotive, Niehoff Ignition systems, Standard Motor Products, AC Delco and NAPA.

Thanks all.

:us:
RTFM

1989 Jeep Cherokee Laredo L6 4.0 5sp

Has been running top notch for quite some time now, in fact was o ut and about running Christmas errands yesterday with no indication of abnormality.

Decided to go get a pizza for supper, jumped in and while driving all electrical flashed off, lights running stereo all if it. It was no more than 1/3 of a second of "off"
A mile or so later it happened again 1/3 of a second and all back to normal.

Out of truck, get pie, in to truck and NOTHING.
No click on ignition, no lights, no starter - nothing. Like no batter was persent under hood.

I know battery is good (less than a year old) but wiring is probably original. just before I call wife to make the rescue I grab the POS battery wife and give it a good shake - more out of frustration than anything else.

I hear three clicks. Click (Like a relay closing) Click (Like relay contacts opening up) CLICK like positive closure of a relay.

Looking at the wiring diagrams today it looks like the only real MASTER throughput of power is the Starter relay which most all vehicle power passes through before going from battery out in to vehicle.

Am I missing anything in my observation of power distribution and could my starter relay be the issue?
- AND -
Looking online I see prices from $19.99 to $64.99 Autozone, Schucks (Checker O'Riley) NAPA
Is there any actual difference in quality - is it a get what you pay for part?
My selection manufacturers are BWD Automotive, Niehoff Ignition systems, Standard Motor Products, AC Delco and NAPA.

Thanks all.

:us:
RTFM

Hmm Sorry for the double post.... don't know how I pulled it off - mods can you remove the other post of the same name - strange.....
Thanks.

Re: A question n starter relays

On Renix XJs the PDC is the lug on the starter relay. It has NOTHING to do with the relay, it is just a convenient place to hang things from.

Your problem is continuity. You need to do Cable 101.

Check your battery, and make sure it is charged. It may be new, but it could be in a discharged state. Remove the cables from the battery, and then disconnect the cables from the vehicle. Clean both ends of the cables, and using a multimeter set for ohms check their resistance--should be at or near ZERO; if not replace the cables. Try and get 4 ga., the stock size are, shall we say, wimpy?

Read this article: http://www.olypen.com/craigh/charge.htm

You need to renew all the main system grounds--dipstick tube (ICM, ECU, o2 sensor), replace the crummy braided strap from the rear of the head to the firewall with a 4 ga. cable--the one and only unibody ground the system has to work with. I recommend running an extra body ground from the batt. neg. terminal to the passenger side fenderwell.

Since you are fixing things, don't forget to check the fuse block. When the brake or clutch MC leak they like to puke fluid and it runs down and eats the fuse block.

From the starter relay's PDC lug those wires all have fusible links, and you need to check those.

RTFM said:

Hmm Sorry for the double post.... don't know how I pulled it off - mods can you remove the other post of the same name - strange.....
Thanks.

Click to expand...

Great, I already posted in the other thread, and now you want the mods to throw it out? Where's the gratitude? :wow:

Should I reply here it will just perpetuate the insanity .... sorry Joe... heading over there now always appreciative for your pearls of wisdom.

Mods. PLEASE combine all to a single thread and stop the insanity....

:us:
R

Re: A question n starter relays

Thanks Joe (as always) I did notice two things of mention, the connection point of the two feeder wires from the Bat Pos connector (A strap looking device on the POS term lug) where the two main wires come from is "slightly lose" so I'll need to remove, clean and re-tighten.

Also fond a crack in the insulation from the bat NEG to block area which is visibly corroded - so that baby needs to be replaced.

I HATE working in the cold.... *sigh* but will do - start checking grounds, and cleaning - tightening POS cable connections.

As always - Thank you and Merry Christmas (every one also)


:us:
RTFM

Re: A question n starter relays

RTFM said:

Thanks Joe (as always) I did notice two things of mention, the connection point of the two feeder wires from the Bat Pos connector (A strap looking device on the POS term lug) where the two main wires come from is "slightly lose" so I'll need to remove, clean and re-tighten.

Also fond a crack in the insulation from the bat NEG to block area which is visibly corroded - so that baby needs to be replaced.

I HATE working in the cold.... *sigh* but will do - start checking grounds, and cleaning - tightening POS cable connections.

As always - Thank you and Merry Christmas (every one also)


:us:
RTFM

Click to expand...

Same for you and yours! Don't forget to post up and let us know what fixes it.

Threads merged.

The starter motor relay failing will only cause the starter to fail to crank (presuming everything else it up to scratch.)

For the full power distribution problem, check the short feeder lead off of the battery POS terminal to the starter motor relay screwpost. I've had those corrode through just short of the clamp (it's not sealed against intrusion there,) and the connexion goes from "spotty" to "NFW." Replacement of the battery cables will see to that little nuisance (chances are, if you turn the key on and get nothing, you can check that connexion by simply fiddling with the wire and seeing if everything comes on.)