95 Astro Strange Electrical

[norcaltim]

I have a high mileage 95 Astro that has developed a strange electrical problem over the past few months. ECM & fuel pump have been replaced. (no change other than lowering my bank account).
A few symptoms.
Occasional the 20 amp ecm fuse will open (found this after the fact replacements)

None of the accessories work unless the key switch is in the ignition on posistion. (dome light, cig lighter, lose radio presets, etc)

Checking the fuse holder with a meter, no voltage on the acc when the key is in the acc position. Voltage when the key is in ignition on position.

I've looked for ground problems checked wiring & am ready to buy a manual with a wiring diagram. Anyone have any suggestions ?

[Blue Bowtie]

The radio backup power, dome light, and cigar lighter should have constant 12V power regardless of the ignition switch. I'm not sure on the '95 bodies, but there may be fusible links at the starter OR an underhood electrical center with body/chassis fuses.

These might help locate some of the fusible links (AllData schematics provided by AutoZone):

[norcaltim]

Got some time to work on this today. Looking at the fuseable links, & tracing wiring, I found I lost the 12v accessories voltage at the connector in back of the battery. There are four power leads coming off the connector one was not hot. I found the voltage was lost at the connector not an open link. I used a scribe to bend the fingers in the connector & Vallaha all the accessories started working (dome lights, cig lighter, radio presets). I thought I was done. Van started & ran well everthing still OK, turned the key off... still running & engine check & seat belt light still on. Tried several things & The van kept running. I thought I'd pull the ecm/fuel pump fuse to shut it off & pulled the ecmb (15a) fuse.. Everything works right with that fuse out.

A couple of key points a few different mechs worked on this before I tried to trace the wiring. One may have "fixed" it by bridging the acc & ign "hots".
This would be why it ran & lights worked with the key only in the Ignition position. Now That acc are "hot" as they should be this path may supply voltage to the ign. My question is what is the ecmb fuse for ? This is not the 20a ECM/Fuel pump fuse.

[sreve]

ecm-b feeds the fuel pump relay. haynes manuals can be good or they suc. alldata 1car 1 year about $25 and worth it

[tedhontz]

I too am having a similar problem. Just bought a 95 safari awd. None of the dome lights work and the cigarette lighter doesn't work either. When I turn the vehicle off, the radio always loses its time and station memory. Also, I have no instrument cluster illumination. I do however have working headlights and everything seems to run okay. I checked the CIG LTR/DM fuse and it was blown. I replaced it and had working domelights all of the sudden and radio is now okay. But the fuse keeps blowing. Also, even when the dome lights were working, I never had instrument gauge illumination. The GAGES fuse is not blown, but it may not be working at all. I have no ash tray illumination or headlight switch illumination also. Any ideas to help me?