Hi all. When I bought my 1999 Bonne, I found the fog lights were not coming on. I checked voltage at the lights and there isn't any. The light in the fog lamp switch also does not light up. I checked both the fuse and the relay behind the passenger kick panel and both were OK. Is there another relay or fuse in the chain I should check and if so, where is it located?

I also wanted to find out if someone that has a factory manual for a 97-99 vintage Bonne and a scanner would be kind enough to either post or email me the page of the wiring diagram that shows the fog lights and interconnections back to the headlight switch.

Thanks much.

My schematics don't cover your car, but someone will step up soon with some help.

Well, I don't have schematics on the 99'*, but may be able to offer a little help. When you checked for power at the fog light connectors, did you use an independent point on the chasis (one probe of meter on +12v pin, other probe on steel frame of car) , or did you place meter across the two pins in the connector? It could be just a simple open in that ground ckt. for the two fog lamps. But since you said the fog light indicator LED is not illuminated either (with ign on & press fog light sw), could suggest another prob in a different area of the fog light control ckt. In the 2000+ Bonnevilles, the Dash Integration Module (DIM) provides ground(when request for fog lamps initiated) for the fog lamp relay. The DIM, and the Instrument Panel Integration Module (IPM) are linked via serial data bus. The fog light switch is direct wired to the IPM which monitors the state of the fog light sw "open or closed". The 99 Bonnevilles may be similar in operation. It can get somewhat complex here. Do your high beams operate normal? They are interlocked with the fog lights. I'm sure some of the more knowledgeable 96-99 guys will probably jump in shortly. Good luck with it.

Fog Lamps Inoperative - All Pontiac
Step
Action
Value(*)
Yes
No

1
Did you perform the entire Foglights System Check?
--
Go to Step 2
Go to Fog Lights System Check

2
Turn the headlamp switch to the PARK position.
Disconnect the fog lamp switch connector.
Connect a DMM from the fog lamp switch connector cavity 2 (BRN) to ground.
Is the voltage within the specified range?
10-15V
Go to Step 3
Go to Step 8

3
Remove the fog lamps relay from the RH IP fuse block.
Reconnect the fog lamp switch connector.
Turn the fog lamp switch to the ON position.
Connect a DMM from the fog lamps relay connector cavity 85 (YEL) to ground.
Is the voltage within the specified range?
10-15V
Go to Step 4
Go to Step 9

4
Connect a DMM from the fog lamps relay connector cavity 30 (ORN) to ground.

Is the voltage within the specified range?
10-15V
Go to Step 5
Go to Step 10

5
Connect a fused jumper between the fog lamps relay connector cavity 30 (ORN) and cavity 87 (PPL).

Do the fog lamps turn on?
--
Go to Step 6
Go to Step 11

6
Disconnect the lamp control module (LCM) connector C2.
Reinstall the fog lamps relay.
Turn the fog lamp switch to the ON position.
Connect a fused jumper between the LCM connector C2 cavity A4 (DK GRN/WHT) and ground.
Do the fog lamps turn on?
--
Go to Step 7
Go to Step 12

7
Replace the LCM. Refer to Lamp Control Module Replacement .

Is the repair complete?
--
Go to Fog Lights System Check
--

8
Repair the open in CKT 9 (BRN) between S204 and the fog lamp switch. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?
--
Go to Fog Lights System Check
--

9
Inspect CKT 317 (YEL) for an open or short to ground. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems.

Is CKT 317 (YEL) OK?
--
Go to Step 13
Go to Step 14

10
Repair the open or short to ground in CKT 1440 (ORN). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?
--
Go to Fog Lights System Check
--

11
Repair the open or short to ground in CKT 34 (PPL). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?
--
Go to Fog Lights System Check
--

12
Inspect CKT 1317 (DK GRN/WHT) for an open. Refer to Testing for Continuity in Wiring Systems.

Is CKT 1317 (DK GRN/WHT) OK?
--
Go to Step 15
Go to Step 14

13
Replace the fog lamp switch. Refer to Trim Panel Replacement - Instrument Panel (I/P) Cluster in Instrument Panel, Gauges and Console.

Is the repair complete?
--
Go to Fog Lights System Check
--

14
Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?
--
Go to Fog Lights System Check
--

15
Replace the fog lamps relay.

Is the repair complete?
--
Go to Fog Lights System Check
--

Damn! all that just to check foglights? I hardly use mine anymore (after the 50wtt incident)
going aftermarket would be a better choice anyway,

Foghorn, thanks for the step by step procedure. I'll check it out today and see what I find out.

Turns out I got lucky and the problem was a pin in the connector that goes to the fog light switch had gotten pushed out of its connector just enough that there was no contact. Reseated the contact and the fog lights worked!

Only bad thing was I managed to break off one of the two plastic retaining clips for the switch housing as careful as I was trying to be with a putty knife to push them back. Oh well.... Fortunately, one clip seems to hold the switch housing to the roof retainer bracket just fine. Of course without a manual, I was just guessing how many clips there were and their locations by feel. I wonder if the manual would have shown some detail around the mounting of the switch housing to the roof bracketry?

Glad to hear you resolved the problem, good piece of troubleshooting. The GM Service Manuals are pretty comprehensive books. They are definitely worth the cost if you plan to keep your car for any lenght of time.