Where is the ALT idiot light on 1988 burb?

[Frankenchevy]

My alternator isn’t charging and I only see 12V on the pink wire at the alternator with key on, but nothing on the brown wire.

You must be registered for see images attach

I thought the brown was the exciter, but could be mistaken. Either way, no idiot light on in the dash. Which position is the ALT idiot light in? Is there an idiot light on 1988 burbs?

You must be registered for see images attach

 

[CountKrunk]

My 84c20 with the idiot gauges came with one so i imagine yours did as well. It's also a low optioned rig so i assume it was standard

 

[Frankenchevy]

My 84c20 with the idiot gauges came with one so i imagine yours did as well. It's also a low optioned rig so i assume it was standard

Do you know where abouts the light was located in the dash? i.e. next to the seatbelt light, or lower left under the battery gauge?

 

[gmbellew]

Do you know where abouts the light was located in the dash? i.e. next to the seatbelt light, or lower left under the battery gauge?

My 90 has it lower left under the voltmeter

 

[Frankenchevy]

My 90 has it lower left under the voltmeter

You must be registered for see images attach

I guess I don’t have one.

 

[Frankenchevy]

Is the pink wire the exciter wire?

If so, I have 12 V there with ignition on. Also, if so… Is the other wire for the battery gauge?

 

[Jgonick]

Usually-

-Brown wire is exciter (Brn 25) if you do not have an idiot light, the brown 25 wire turns into brn/white 130 and connects to the ignition switch at ign3 spot. (Side note- the brn/white 130 wire has a 10+ohm resistance - so no need for light to add resistance)

If you do have an idiot light the Brn25 wire runs to the cluster connection (to light that is fed by brn 50 wire)

Edited to correct a mistake for future reading- idiot light is generally fed by brn50 not pnk/blk 39

 

[Frankenchevy]

Usually-

-Brown wire is exciter (Brn 25) if you do not have an idiot light, the brown 25 wire turns into brn/white 130 and connects to the ignition switch at ign3 spot. (Side note- the brn/white 130 wire has a 10+ohm resistance - so no need for light to add resistance)

If you do have an idiot light the Brn25 wire runs to the cluster connection (to light that is fed by pink39 wire)

What is the pink/blk stripe wire with 12v key on at the alternator SFLP harness?

You must be registered for see images attach

 

[Jgonick]

The pink/blk wire confuses me- you usually do not see it at alternator on 1988 r/v. Note- In 1987 square bodies changed from c/k to r/v

 

[Frankenchevy]

The pink/blk wire confuses me- you usually do not see it at alternator on 1988 r/v. Note- In 1987 square bodies changed from c/k to r/v

What colors would you typically see and in which location (location referring to S F L P)?

 

[bucket]

Usually-

-Brown wire is exciter (Brn 25) if you do not have an idiot light, the brown 25 wire turns into brn/white 130 and connects to the ignition switch at ign3 spot. (Side note- the brn/white 130 wire has a 10+ohm resistance - so no need for light to add resistance)

If you do have an idiot light the Brn25 wire runs to the cluster connection (to light that is fed by pink39 wire)

Can you show a factory schematic that shows a restistance wire? I have never found one.

 

[Jgonick]

Just some of my notes on alternators.

Resistance brn/wht 130 wire: A lot of the diagrams show it- it is just sort of hidden-

Several Attachments: examples 83 & 86 Wiring diagrams showing resistance wire. Also a general diagram. Also in Service Manual, & 84 wiring showing it at ignition switch. it is pretty hard to find it in all the wiring diagrams consistently.

 

[Jgonick]

attachments: Alternator terminals for CS, recommendations for CS.

If you are using an CS alternator use the I terminal for exciter (it takes either- has built in resistance)

Several sources say to use roughly 50 ohms resistance (resistor) if connecting to L terminal (or use a bulb) especially for the CS alternator.

My research says 10 ohms for SI alternator (see service manual attachment in above post)

Here is a LINK to the Alternator Bible- I found it very informative.

 

[Jgonick]

What colors would you typically see and in which location (location referring to S F L P)?

Generally on a CS alt. "L" or "I" is used as exciter (BRN 25 wire) And "S" (sensing) is usually red.

I’m curious - Check your alternator and see if the terminals are labeled like the connector.

 

[Frankenchevy]

I’m curious - Check your alternator and see if the terminals are labeled like the connector.

Will do. It’s an aftermarket alternator, but I should still have the original around as well.